TWI667197B - Method for preparing graphene-yttria composite material, graphene-yttria composite material and application thereof - Google Patents

Abstract

本創作提供一種石墨烯-氧化鉍複合材料製備方法及其製備而得的石墨烯-氧化鉍複合材料。該製備方法包括以下步驟：步驟(a)：製備氧化石墨烯水溶液；步驟(b)：混合該氧化石墨烯水溶液和硝酸鉍水溶液，在溫度為150°C至250°C、壓力為0.5百萬帕至1.5百萬帕進行水熱反應，以得到還原氧化石墨烯-氧化鉍的前驅物；以及步驟(c)：將該前驅物以250°C至600°C進行煆燒，以得到石墨烯-氧化鉍複合材料。此外，包含前述石墨烯-氧化鉍複合材料的電極材料具有良好電性特質，適用於超級電容器。The present invention provides a method for preparing a graphene-yttria composite material and a graphene-yttria composite material prepared therefrom. The preparation method comprises the following steps: step (a): preparing an aqueous graphene oxide solution; and step (b): mixing the aqueous graphene oxide solution and an aqueous solution of rhodium nitrate at a temperature of 150 ° C to 250 ° C and a pressure of 0.5 million a hydrothermal reaction to 1.5 MPa to obtain a precursor of reduced graphene oxide-yttria; and step (c): the precursor is calcined at 250 ° C to 600 ° C to obtain graphene - yttrium oxide composite. Further, the electrode material comprising the aforementioned graphene-yttria composite material has good electrical properties and is suitable for use in a supercapacitor.

Description

石墨烯-氧化鉍複合材料的製備方法、石墨烯-氧化鉍複合材料及其應用Method for preparing graphene-yttria composite material, graphene-yttria composite material and application thereof

本創作係有關一種包含石墨烯的複合材料，尤其是指一種還原氧化石墨烯-氧化鉍複合材料，本創作還有關於製造該石墨烯-氧化鉍複合材料的方法以及將該石墨烯-氧化鉍複合材料應用於電極材料和超級電容器。The present invention relates to a composite material comprising graphene, in particular to a reduced graphene oxide-yttria composite material, and a method for producing the graphene-yttria composite material and the graphene-yttria Composite materials are used in electrode materials and supercapacitors.

隨著社會發展，石油、煤炭等傳統化石能源的使用量大增，然而燃燒化石能源後產生的溫室氣體大量被釋放，造成全球氣候變異、物種消失與冰川融化等問題，且燃燒後產生的超細懸浮微粒使得空氣品質下降，同時會危害人體健康；因此各國正積極發展包括低碳、再生能源等綠色科技，而再生能源發展的關鍵之一即是儲能系統的開發。儲能系統中的超級電容器因其具有快速的充放電性能而備受矚目，然而，超級電容器因儲存能量密度不及鋰離子電池，限制了超級電容器的應用；因此，尋找具高循環壽命、高容量之電極材料以應用於超級電容器係為業界積極努力的目標。With the development of society, the use of traditional fossil energy such as oil and coal has increased greatly. However, the greenhouse gases generated after burning fossil energy have been released in large quantities, causing problems such as global climate variability, species disappearance and melting of glaciers, and Fine aerosols reduce air quality and endanger human health; therefore, countries are actively developing green technologies including low-carbon, renewable energy, and one of the keys to the development of renewable energy is the development of energy storage systems. Supercapacitors in energy storage systems are attracting attention due to their rapid charge and discharge performance. However, supercapacitors limit the application of supercapacitors due to their lower energy density than lithium ion batteries; therefore, they are looking for high cycle life and high capacity. The electrode material is actively used in the industry for the application of the supercapacitor system.

目前，將比表面積大、電導率高、化學穩定性好的石墨烯應用於超級電容器可提高超級電容器的能量容量；但以機械剝除法的石墨烯不易控制石墨烯的厚度及尺寸，難以推廣到產業端實際使用，且石墨烯之間容易產生團聚，不利於後續應用；另外，Hummers開發以硝酸鈉、過錳酸鉀和濃硫酸等氧化劑，將含氧官能基引入石墨烯層間與邊界，克服石墨烯層間的凡得瓦力，進而可大量剝離出石墨烯，但過程中常使用二甲基甲醯胺(dimethylformamide，DMF)、N-甲基吡咯烷酮(N-Methyl-2-pyrrolidone，NMP)等有毒性的有機溶劑，與綠色化學概念背道而馳。At present, the application of graphene with large specific surface area, high conductivity and good chemical stability to supercapacitors can improve the energy capacity of supercapacitors; however, graphene with mechanical stripping method is difficult to control the thickness and size of graphene, and it is difficult to generalize to The industrial end is actually used, and graphene is prone to agglomeration, which is not conducive to subsequent applications. In addition, Hummers develops oxidants such as sodium nitrate, potassium permanganate and concentrated sulfuric acid to introduce oxygen-containing functional groups into the graphene layer and boundary to overcome The van der Waals force between the graphene layers can further remove graphene in a large amount, but dimethylformamide (DMF), N-methylethylpyrrolidone (NMP), etc. are often used in the process. A toxic organic solvent runs counter to the concept of green chemistry.

有鑑於上述現有技術所面臨之技術缺陷，本創作之目的在於提供一種石墨烯-氧化鉍複合材料的製備方法，因製備過程中不使用有毒的有機溶劑，因而對環境更友善。In view of the technical defects faced by the above prior art, the purpose of the present invention is to provide a method for preparing a graphene-yttria composite material, which is more environmentally friendly because no toxic organic solvent is used in the preparation process.

本創作之另一目的在於提供一種石墨烯-氧化鉍複合材料的製備方法，有利業界在製備相關材料的應用時，能符合經濟成本及生產效率，進而提高商業量產的開發潛力。Another object of the present invention is to provide a method for preparing a graphene-yttria composite material, which is advantageous for the industry to meet the economic cost and production efficiency in the preparation of related materials, thereby improving the development potential of commercial mass production.

為達成前述目的，本創作提供一種石墨烯-氧化鉍複合材料的製備方法，包括以下步驟：步驟(a)：製備氧化石墨烯水溶液；步驟(b)：混合該氧化石墨烯水溶液和硝酸鉍水溶液，在溫度為150°C至250°C、壓力為0.5百萬帕(MPa)至1.5 MPa下進行水熱反應，以得到還原氧化石墨烯-氧化鉍的前驅物；以及步驟(c)：將該前驅物以250°C至600°C進行煆燒，以得到石墨烯-氧化鉍複合材料。In order to achieve the foregoing object, the present invention provides a method for preparing a graphene-yttria composite material, comprising the steps of: step (a): preparing an aqueous graphene oxide solution; and step (b): mixing the aqueous graphene oxide solution and an aqueous solution of rhodium nitrate a hydrothermal reaction at a temperature of 150 ° C to 250 ° C and a pressure of 0.5 MPa to 1.5 MPa to obtain a precursor of reduced graphene oxide-yttria; and step (c): The precursor is calcined at 250 ° C to 600 ° C to obtain a graphene-yttria composite.

本創作藉由高壓釜內維持一定的溫度及密閉條件，使得石墨烯和硝酸鉍可在比固相反應溫度低的溫度下即能進行無機合成反應，進而減少製程的能源消耗，且製備過程中皆在水溶液中進行，不含有毒的有機溶劑；接著，透過煆燒獲得石墨烯-氧化鉍複合材料。另外，本創作以熱還原與再氧化之機制，因而可獲得副產物(如Bi ₂O ₂(CO ₃))較少的複合材料。 The present invention maintains a certain temperature and sealing conditions in the autoclave, so that graphene and lanthanum nitrate can perform inorganic synthesis reaction at a temperature lower than the solid phase reaction temperature, thereby reducing the energy consumption of the process, and during the preparation process. They are all carried out in an aqueous solution and do not contain a toxic organic solvent; then, a graphene-yttria composite material is obtained by calcination. In addition, the present invention uses a mechanism of thermal reduction and reoxidation, so that a composite material having less by-products such as Bi ₂ O ₂ (CO ₃ ) can be obtained.

較佳的，該步驟(b)中所含的氧化石墨烯和硝酸鉍之固體重量比介於1：0.1至1：1.2；在此範圍內，能提供適量的氧化鉍顆粒，使該石墨烯-氧化鉍複合材料具有分布性佳且團聚效應低的效果。Preferably, the weight ratio of the graphene oxide to the cerium nitrate contained in the step (b) is from 1:0.1 to 1:1.2; in this range, an appropriate amount of cerium oxide particles can be provided to make the graphene - The cerium oxide composite material has a good distribution effect and a low agglomeration effect.

較佳的，在該步驟(b)中，以pH值為大於或等於8，且小於10的條件下，進行水熱反應。隨著步驟(b)之水溶液的酸鹼度(pH值)增加，過多的氫氧根(OH ^-)可能致使鉍的氫氧化物團聚嚴重而形成沉澱；因此，在適當的pH值範圍內，不僅能達到控制氧化鉍顆粒大小(尺寸約介於10 nm至50 nm間)的效果，更能提升石墨烯夾層中對於氧化鉍顆粒的包覆性。 Preferably, in the step (b), the hydrothermal reaction is carried out under the condition that the pH is greater than or equal to 8, and less than 10. As the pH of the aqueous solution of step (b) increases, excessive hydroxide (OH ^- ) may cause agglomeration of the hydroxide of the hydrazine to form a precipitate; therefore, in a suitable pH range, not only The effect of controlling the particle size of the cerium oxide (between about 10 nm and 50 nm) can improve the coating of cerium oxide particles in the graphene interlayer.

在一些實施例中，該步驟(a)可包括：步驟(a1)：將石墨片加入一含硫酸和磷酸的混合酸液中，得到一石墨片溶液；步驟(a2)：該石墨片溶液於溫度5°C至50°C下加入過錳酸鉀進行反應，再佐予進行超音波震盪，得到一混合溶液；步驟(a3)：於溫度40°C至120°C下，持續攪拌該混合溶液1小時至24小時；步驟(a4)：冷卻該混合溶液的溫度至-5°C至20°C後加入雙氧水，再經過離心、乾燥步驟，得到氧化石墨烯固體；以及步驟(a5)：將該氧化石墨烯固體與水混合，以得到該氧化石墨烯水溶液。前述製備氧化烯係以改良悍馬法(Improved Hummer’s method)為基礎，輔以超音波震盪(ultra-sonication)，可使含氧官能基更充分地吸附於石墨層的表面，破壞石墨層整齊的sp ²結構，有效增加石墨層的氧化程度，均勻撐擴石墨片層的間距，藉此使石墨層間賴以結合的凡得瓦力效應減退；並藉由超音波震盪提供的能量，更能促使拆離石墨層，達到控制石墨烯厚度、尺寸的效果。 In some embodiments, the step (a) may include: step (a1): adding a graphite sheet to a mixed acid solution containing sulfuric acid and phosphoric acid to obtain a graphite sheet solution; and step (a2): the graphite sheet solution is Adding potassium permanganate at a temperature of 5 ° C to 50 ° C for reaction, and then performing ultrasonic vibration to obtain a mixed solution; Step (a3): continuously stirring the mixed solution at a temperature of 40 ° C to 120 ° C 1 hour to 24 hours; step (a4): cooling the temperature of the mixed solution to -5 ° C to 20 ° C, adding hydrogen peroxide, passing through a centrifugation, drying step to obtain a graphene oxide solid; and step (a5): The graphene oxide solid is mixed with water to obtain the aqueous graphene oxide solution. The above-mentioned preparation of the oxyalkylene system is based on the improved Hummer's method, supplemented by ultra-sonication, so that the oxygen-containing functional group can be more fully adsorbed on the surface of the graphite layer, and the graphite layer is destroyed. ² structure, effectively increasing the degree of oxidation of the graphite layer, uniformly spreading the spacing of the graphite sheets, thereby reducing the effect of the combined van der Waals force between the graphite layers; and by the energy provided by the ultrasonic oscillation, the demolition is further promoted From the graphite layer, the effect of controlling the thickness and size of the graphene is achieved.

於前述步驟(a1)中，該硫酸之重量百分濃度為95%至98%；該磷酸之重量百分濃度為75%至85%；該混合酸液中所含的該硫酸與該磷酸的體積比為9：1、該石墨片的重量相對於混合酸液的體積的比例為3：100至3：300。於前述步驟(a2)中，前述石墨片溶液中石墨片的重量相對於過錳酸鉀的重量比例為1：5至1：19。於前述步驟(a4)中，混合溶液相對於雙氧水的體積比為40：1至133：1。經前述步驟(a5)，所配製而成之氧化石墨烯水溶液的體積莫耳濃度為0.02 M至0.06 M。In the foregoing step (a1), the concentration by weight of the sulfuric acid is 95% to 98%; the concentration by weight of the phosphoric acid is 75% to 85%; the sulfuric acid contained in the mixed acid solution and the phosphoric acid The volume ratio is 9:1, and the ratio of the weight of the graphite sheet to the volume of the mixed acid solution is from 3:100 to 3:300. In the foregoing step (a2), the weight ratio of the graphite flakes in the graphite sheet solution to the potassium permanganate is 1:5 to 1:19. In the aforementioned step (a4), the volume ratio of the mixed solution to hydrogen peroxide is from 40:1 to 133:1. Through the foregoing step (a5), the volumetric molar concentration of the aqueous graphene oxide solution prepared is 0.02 M to 0.06 M.

依據本創作，該步驟(c)的煆燒溫度介於250°C至600°C，較佳的，該步驟(c)的煆燒溫度介於280°C至500°C。在一些實施例中，該步驟(c)可包括：步驟(c1)：在氮氣環境中，將該前驅物以400°C至500°C煆燒，得到一粗產物；以及步驟(c2)：在空氣環境中，將該粗產物以280°C至330°C煆燒，得到該石墨烯-氧化鉍複合材料。藉由控制前述煆燒的溫度範圍，不僅可脫去水，同時可使所述前驅物產生熱解離以及發生相轉移而得到β相的氧化鉍(β-Bi ₂O ₃)，而β相的氧化鉍晶體具有氧空缺排列，電子躍遷所需能量很低，因此具有高度的離子導電性。藉由分成兩個階段的煆燒，能使該石墨烯-氧化鉍複合材料的晶型之一致性高，進而降低副產物的產生。 According to the present creation, the calcination temperature of the step (c) is from 250 ° C to 600 ° C. Preferably, the calcination temperature of the step (c) is from 280 ° C to 500 ° C. In some embodiments, the step (c) may comprise the following step (c1): calcining the precursor at 400 ° C to 500 ° C in a nitrogen atmosphere to obtain a crude product; and step (c2): The crude product was calcined at 280 ° C to 330 ° C in an air atmosphere to obtain the graphene-yttria composite. By controlling the temperature range of the calcination, not only water can be removed, but also the precursor can be thermally dissociated and phase-transferred to obtain a β-phase cerium oxide (β-Bi ₂ O ₃ ), while the β phase The yttria crystal has an oxygen vacancy arrangement, and the energy required for the electron transition is low, so that it has a high degree of ionic conductivity. By dividing the two-stage calcination, the crystal form of the graphene-yttria composite can be made uniform, thereby reducing the generation of by-products.

此外，本創作另提供一種如前述石墨烯-氧化鉍複合材料的製備方法所製備而得的石墨烯-氧化鉍複合材料，該石墨烯-氧化鉍複合材料中包含複數氧化鉍顆粒及複數石墨烯層，該等氧化鉍顆粒分佈於該等石墨烯層之間。In addition, the present invention further provides a graphene-yttria composite material prepared by the method for preparing a graphene-yttria composite material, wherein the graphene-yttria composite material comprises a plurality of cerium oxide particles and a plurality of graphene a layer, the cerium oxide particles being distributed between the graphene layers.

較佳的，該複合材料中的各石墨烯層的厚度介於2奈米(nm)至4 nm，且該石墨烯-氧化鉍複合材料中具有4層至8層的石墨烯層。Preferably, each graphene layer in the composite has a thickness of from 2 nanometers (nm) to 4 nm, and the graphene-yttria composite has four to eight layers of graphene layers.

依據本創作，該複合材料中的比表面積介於50平方米/克(m ²/g)至350平方米/克(m ²/g)；較佳的，該複合材料的的比表面積介於70平方米/克(m ²/g)至350平方米/克(m ²/g)。 According to the present invention, the specific surface area in the composite material ranges from 50 m ² /g (m ² /g) to 350 m ² /g (m ² /g); preferably, the specific surface area of the composite material is between 70 m ² /g (m ² /g) to 350 m ² /g (m ² /g).

較佳的，該複合材料的熱分解溫度為380°C至450°C。Preferably, the composite has a thermal decomposition temperature of from 380 ° C to 450 ° C.

較佳的，該複合材料之拉曼光譜分析的G峰介於1587 cm ^-1至1592 cm ^-1。 Preferably, the composite has a G peak of 1587 cm ^-1 to 1592 cm ^-1 by Raman spectroscopy.

此外，本創作另提供一種電極材料，包含前述的石墨烯-氧化鉍複合材料，且該電極材料是用於超級電容器。Further, the present invention further provides an electrode material comprising the aforementioned graphene-yttria composite material, and the electrode material is for a supercapacitor.

較佳的，該電極材料經由3000圈的充、放電測試，其電容量能維持在90%以上，更佳的，其電容量能維持在95%以上。Preferably, the electrode material is capable of maintaining a capacitance of 90% or more via a charge and discharge test of 3000 cycles, and more preferably, the electrode capacity can be maintained at 95% or more.

較佳的，該電極材料經由3000圈的充、放電測試，其庫倫效率能維持在90%以上，更佳的，其庫倫效率能維持在95%以上。Preferably, the electrode material is tested for charge and discharge over 3000 cycles, and the coulombic efficiency can be maintained above 90%. More preferably, the coulombic efficiency can be maintained above 95%.

在下文中，本領域技術人員可從以下實施例很輕易地理解本創作所能達到的優點及效果。因此，應當理解本文提出的敘述僅僅用於說明優選的實施方式而不是用於侷限本創作的範圍，在不悖離本創作的精神和範圍的情況下，可以進行各種修飾、變更以便實施或應用本創作之內容。Hereinafter, those skilled in the art can easily understand the advantages and effects that can be achieved by the present invention from the following embodiments. Therefore, it is to be understood that the descriptions of the present invention are only intended to illustrate the preferred embodiments and are not intended to limit the scope of the present invention. The content of this creation.

以下實施例所用儀器廠牌及型號： 1. 超音波震盪機：DELTA DC200H； 2. 高壓釜：購自鴻祺精密科技公司； 3. X射線繞射分析儀：BRUKER D8 Discover； 4. 解析型掃描穿透式電子顯微鏡：JEOL TEM-3010； 5. 傅立葉紅外光譜儀：PerkinElmer； 6. 高解析場發射型掃描式電子顯微鏡：JEOL JSM-6700F； 7. 多功能掃描探針顯微鏡：BRUKER Dimension Icon； 8. 比表面積分析儀：Micromeritics ASAP 2020； 9. 拉曼光譜儀：Ramboss 500i Micro-Raman； 10. 熱分析儀：TA-SDT Q600。The instrument label and model used in the following examples: 1. Ultrasonic oscillator: DELTA DC200H; 2. Autoclave: purchased from Hongjun Precision Technology Co., Ltd.; 3. X-ray diffraction analyzer: BRUKER D8 Discover; 4. Analytical Scanning transmission electron microscope: JEOL TEM-3010; 5. Fourier infrared spectrometer: PerkinElmer; 6. High resolution field emission scanning electron microscope: JEOL JSM-6700F; 7. Multifunctional scanning probe microscope: BRUKER Dimension Icon; 8. Specific surface area analyzer: Micromeritics ASAP 2020; 9. Raman spectrometer: Ramboss 500i Micro-Raman; 10. Thermal analyzer: TA-SDT Q600.

以下實施例所使用的原料： 1. 天然石墨片：325 mesh，購自Alfa Aesar； 2. 磷酸：購自SHOWA； 3. 硫酸：純度99.5%，購自Scharlau； 4. 過錳酸鉀：potassium permanganate (KMnO ₄)，購自Panreac； 5. 硝酸鉍：bismuth(III) nitrate (Bi(NO ₃) ₃)，購自ACROS； 6. 聚四氟乙烯：polytetrafluoroethene (PTFE)，購自Alfa Aesar。 The materials used in the following examples: 1. Natural graphite flakes: 325 mesh, purchased from Alfa Aesar; 2. Phosphoric acid: purchased from SHOWA; 3. Sulfuric acid: 99.5% purity, purchased from Scharlau; 4. Potassium permanganate: potassium Permanganate (KMnO ₄ ), purchased from Panreac; 5. Barium nitrate: bismuth (III) nitrate (Bi(NO ₃ ) ₃ ), available from ACROS; 6. Polytetrafluoroethylene: polytetrafluoroethene (PTFE), available from Alfa Aesar.

製備例Preparation example 11 ：氧化石墨烯: Graphene oxide 固體solid 之製備Preparation

將3克石墨片原料加入一包含濃硫酸(濃度為98%)和磷酸(濃度為85%)的混合酸液200毫升(該濃硫酸和磷酸的體積比為9:1)中，使用均質機以600每分鐘轉速(rpm)進行攪拌1小時，再以超音波震盪機進行30分鐘的震盪，得到一石墨片溶液；利用低溫循環水槽控制反應溫度至10°C，緩慢添加12克過錳酸鉀，持續攪拌2小時，再以超音波震盪機進行30分鐘的震盪；隨後，將反應溫度提高至50°C，以500 rpm進行攪拌12小時，再次以超音波機進行震盪30分鐘，靜置混合溶液冷卻至室溫，得到一混合溶液；將冰塊加入該混合溶液中，使該混合溶液的溫度為-5°C至20°C，再緩慢添加10 mL雙氧水使反應終止，此時溶液呈現金黃色；重複進行數次離心並以5%鹽酸溶液酸洗步驟，直至確認硫酸根去除後，改以二次去離子水進行數次水洗，直至溶液接近中性(pH為7)；接著，放置於50°C真空烘箱內24小時，即得到氧化石墨烯固體。Add 3 g of graphite flakes to a mixed acid solution containing concentrated sulfuric acid (concentration of 98%) and phosphoric acid (concentration of 85%) in 200 ml (the volume ratio of concentrated sulfuric acid to phosphoric acid is 9:1), using a homogenizer Stirring at 600 rpm for 1 hour, and then shaking with a ultrasonic oscillating machine for 30 minutes to obtain a graphite sheet solution; using a low temperature circulating water tank to control the reaction temperature to 10 ° C, slowly adding 12 g of permanganic acid Potassium, stirring for 2 hours, and then shaking for 30 minutes with an ultrasonic oscillator; then, raising the reaction temperature to 50 ° C, stirring at 500 rpm for 12 hours, shaking again with an ultrasonic machine for 30 minutes, and letting stand The mixed solution is cooled to room temperature to obtain a mixed solution; ice cubes are added to the mixed solution, the temperature of the mixed solution is -5 ° C to 20 ° C, and 10 mL of hydrogen peroxide is slowly added to terminate the reaction. Rendering golden yellow; repeating several centrifugation and pickling step with 5% hydrochloric acid solution until after confirming sulfate removal, change to secondary deionized water for several times of water washing until the solution is close to neutral (pH 7); , placed in a vacuum oven at 50 ° C 24 In an hour, a graphene oxide solid is obtained.

製備例Preparation example 22 ：氧化石墨烯水溶液之製備: Preparation of aqueous graphene oxide solution

取0.1克的氧化石墨烯固體與40 mL水混合，以超音波震盪機進行1小時的震盪，即得到氧化石墨烯水溶液。0.1 g of graphene oxide solid was mixed with 40 mL of water, and shaken for 1 hour with an ultrasonic oscillating machine to obtain an aqueous graphene oxide solution.

分析analysis 11 ：: XRDXRD 分析analysis

圖1由上至下依序為製備例1之氧化石墨烯固體和石墨片原料以X射線繞射分析儀(X-ray diffractometer，XRD)分析其晶相結構所得到的繞射圖譜以及石墨片的標準繞射圖譜(JCPDS卡號41-1487)。如圖1所示，該石墨片原料於2θ為26.37(002)，此繞射峰可對應至石墨的標準繞射圖譜(JCPDS 41-1487)相同；而製備例1之氧化石墨烯固體因經強氧化劑作用後，導致石墨烯中的層距增大，導致繞射峰偏移，因此其晶面轉為(001)，特徵峰則出現於10.78°左右。並且，藉由布拉格定律(Bragg’s Law)計算得知，石墨片原料之晶面層間距為0.34奈米，而氧化石墨烯固體之晶面層間距則為0.83奈米。Fig. 1 is a diffraction pattern and a graphite sheet obtained by analyzing the crystal phase structure of the graphene oxide solid and the graphite sheet raw material of the preparation example 1 by X-ray diffractometer (XRD) from top to bottom. Standard diffraction pattern (JCPDS card number 41-1487). As shown in FIG. 1, the graphite sheet material has a 2θ of 26.37 (002), and the diffraction peak can be the same as the standard diffraction pattern of graphite (JCPDS 41-1487); and the graphene oxide solid of the preparation example 1 is After the action of strong oxidant, the interlayer distance in graphene increases, which causes the diffraction peak to shift, so its crystal plane turns to (001), and the characteristic peak appears at about 10.78°. Further, it was calculated by Bragg's Law that the interplanar spacing of the graphite sheet raw material was 0.34 nm, and the interplanar spacing of the graphene oxide solid was 0.83 nm.

分析analysis 22 ：電子繞射圖:Electronic diffraction pattern

利用解析型掃描穿透式電子顯微鏡(Analytical scanning transmission electron microscopy)分析原料之石墨片和製備例1之氧化石墨烯的電子繞射點圖(diffraction patterns)。如圖2A所示，因石墨片包含相當多層的石墨烯，因此其繞射晶面會重疊，因此造成多點成環或光點拖尾的現象；而如圖2B所示，製備例1之氧化石墨烯呈現典型的石墨烯六角環狀之電子繞射光點，與圖2A之環形光圈有顯著的差異，由此可證明，製備例1之氧化石墨烯為低層數的結構。The electron diffraction diffraction patterns of the graphite sheet of the raw material and the graphene oxide of Preparation Example 1 were analyzed by an analytical scanning transmission electron microscopy. As shown in FIG. 2A, since the graphite sheet contains a relatively large number of graphenes, the diffraction crystal planes overlap, thereby causing a phenomenon of multi-point looping or spot tailing; and as shown in FIG. 2B, the preparation example 1 Graphene oxide exhibits a typical graphene hexagonal ring-shaped electron diffraction spot, which is significantly different from the annular aperture of FIG. 2A, and thus it can be confirmed that the graphene oxide of Preparation Example 1 has a low layer number structure.

實施例Example 11 之石墨烯Graphene -- 氧化鉍複合材料Cerium oxide composite

5毫升濃硝酸水溶液溶解0.01克硝酸鉍形成一硝酸鉍水溶液，將前述製備例2得到的氧化石墨烯水溶液倒入該硝酸水溶液中，其中，氧化石墨烯和硝酸鉍之固體重量比為1：0.1，先以超音波震盪機進行30分鐘的震盪，再以300 rpm攪拌並同時滴加濃氨水調整溶液的pH值至8.5，再持續攪拌30分鐘，得到一含有氧化石墨烯的混合溶液；將該含有氧化石墨烯的混合溶液轉移至100毫升之高壓釜中，以每分鐘5°C的升溫速度升溫至180°C(壓力約為1.0 MPa)，且恆溫12小時並進行水熱反應，以得到還原氧化石墨烯-氧化鉍的前驅物；待反應完成後，將得到的沉澱物取出，接著以二次去離子水與無水酒精各洗滌該沉澱物數次後，放置於80°C真空烘箱內12小時，得到該前驅物固體。5 ml of concentrated aqueous nitric acid solution was dissolved in 0.01 g of cerium nitrate to form an aqueous solution of cerium nitrate, and the aqueous graphene oxide solution obtained in the above Preparation Example 2 was poured into the aqueous solution of nitric acid, wherein the solid weight ratio of graphene oxide to cerium nitrate was 1:0.1. First, shake with a ultrasonic oscillating machine for 30 minutes, then stir at 300 rpm and simultaneously add concentrated ammonia to adjust the pH of the solution to 8.5, and then continue stirring for 30 minutes to obtain a mixed solution containing graphene oxide; The mixed solution containing graphene oxide was transferred to a 100 ml autoclave, and the temperature was raised to 180 ° C (pressure of about 1.0 MPa) at a temperature increase rate of 5 ° C per minute, and the mixture was thermostatically reacted for 12 hours to obtain a hydrothermal reaction. Reducing the precursor of graphene oxide-yttria; after the reaction is completed, the obtained precipitate is taken out, and then the precipitate is washed several times with twice deionized water and anhydrous alcohol, and then placed in a vacuum oven at 80 ° C The precursor solid was obtained for 12 hours.

隨後，在氮氣環境中，將該前驅物放進高溫爐以450°C煆燒2小時，得到一粗產物；再以每分鐘5°C的降溫速度降溫至300°C，接著以空氣進行煆燒30分鐘後，待自然降溫，即得石墨烯-氧化鉍複合材料。Subsequently, the precursor was placed in a high-temperature furnace and calcined at 450 ° C for 2 hours in a nitrogen atmosphere to obtain a crude product; the temperature was lowered to 300 ° C at a cooling rate of 5 ° C per minute, followed by air enthalpy. After burning for 30 minutes, after cooling naturally, a graphene-yttria composite material is obtained.

實施例Example 22 之石墨烯Graphene -- 氧化鉍複合材料Cerium oxide composite

實施例2所採用的方法與製備實施例1之石墨烯-氧化鉍複合材料的方法相似，其差異在於：實施例2所使用的硝酸鉍水溶液係以5毫升濃硝酸水溶液溶解0.03克硝酸鉍所形成，其中，氧化石墨烯和硝酸鉍之重量比為1：0.3。The method used in Example 2 was similar to the method for preparing the graphene-yttria composite material of Example 1, except that the aqueous solution of cerium nitrate used in Example 2 was dissolved in 0.03 g of lanthanum nitrate in 5 ml of concentrated aqueous nitric acid solution. Formed in which the weight ratio of graphene oxide to cerium nitrate is 1:0.3.

實施例Example 33 之It 石墨烯Graphene -- 氧化鉍複合材料Cerium oxide composite

實施例3所採用的方法與製備實施例1之石墨烯-氧化鉍複合材料的方法相似，其差異在於：實施例3所使用的硝酸鉍水溶液係以5毫升濃硝酸水溶液溶解0.06克硝酸鉍所形成，其中，氧化石墨烯和硝酸鉍之重量比為1：0.6。The method used in Example 3 was similar to the method for preparing the graphene-yttria composite material of Example 1, except that the aqueous solution of cerium nitrate used in Example 3 was dissolved in 0.06 g of lanthanum nitrate in 5 ml of concentrated aqueous nitric acid solution. Formed in which the weight ratio of graphene oxide to cerium nitrate is 1:0.6.

實施例Example 44 之It 石墨烯Graphene -- 氧化鉍複合材料Cerium oxide composite

實施例4所採用的方法與製備實施例1之石墨烯-氧化鉍複合材料的方法相似，其差異在於：實施例4所使用的硝酸鉍水溶液係以5毫升濃硝酸水溶液溶解0.09克硝酸鉍所形成，其中，氧化石墨烯和硝酸鉍之重量比為1：0.9。The method used in Example 4 was similar to the method for preparing the graphene-yttria composite material of Example 1, except that the aqueous solution of cerium nitrate used in Example 4 was dissolved in 5 ml of concentrated aqueous nitric acid solution to dissolve 0.09 g of lanthanum nitrate. Formed in which the weight ratio of graphene oxide to cerium nitrate is 1:0.9.

實施例Example 55 之It 石墨烯Graphene -- 氧化鉍複合材料Cerium oxide composite

實施例5所採用的方法與製備實施例1之石墨烯-氧化鉍複合材料的方法相似，其差異在於：實施例5所使用的硝酸鉍水溶液係以5毫升濃硝酸水溶液溶解0.12克硝酸鉍所形成，其中，氧化石墨烯和硝酸鉍之重量比為1：1.2。The method used in Example 5 was similar to the method for preparing the graphene-yttria composite material of Example 1, except that the aqueous solution of cerium nitrate used in Example 5 was dissolved in 5 ml of concentrated aqueous nitric acid solution to dissolve 0.12 g of lanthanum nitrate. Formed in which the weight ratio of graphene oxide to cerium nitrate is 1:1.2.

參考例Reference example 11 之氧化石墨烯固體Graphene oxide solid (( 由製備例Preparation example 11 製得be made of ))

參考例Reference example 22 之還原氧化石墨烯Reduced graphene oxide

將製備例2之氧化石墨烯水溶液置入高壓釜內，以每分鐘5°C的升溫速度升溫至180°C(壓力約為1.0 MPa)，待恆溫12小時後，即得到還原氧化石墨烯。The aqueous graphene oxide solution of Preparation Example 2 was placed in an autoclave, and the temperature was raised to 180 ° C (pressure of about 1.0 MPa) at a temperature elevation rate of 5 ° C per minute. After a constant temperature of 12 hours, reduced graphene oxide was obtained.

分析analysis 33 ：參考例: Reference example 22 、實施例Example 11 至to 55 之It XRDXRD 分析analysis

圖3由下至上依序為參考例2、實施例1至5以X射線繞射分析儀分析其晶相結構的繞射圖譜。如圖3所示，參考例2出現2θ約為26°的寬峰；由於參考例2係由氧化石墨烯還原而得，當氧化石墨烯表面的含氧官能基被移除，部分的石墨烯表面呈現皺摺及無序的堆疊，而恢復了原有晶面(002)，因此出現此特徵峰，表示確實製備出還原氧化石墨烯；由JCPDS標準繞射圖譜(JCPDS 27-0050)可知，於2θ約為28°的繞射峰係β-Bi ₂O ₃的晶面(201)之特徵峰，對照圖3可發現實施例1至5於2θ約為28°的繞射峰強度確實隨著使用的硝酸鉍濃度的提高而增強；然而，由於β-Bi ₂O ₃的晶面訊號較為強烈，相較之下，還原氧化石墨烯的特徵峰則無法被明顯呈現。 3 is a diffraction pattern of the crystal phase structure of the reference example 2 and the examples 1 to 5, which are analyzed by the X-ray diffraction analyzer from bottom to top. As shown in FIG. 3, Reference Example 2 showed a broad peak of 2θ of about 26°; since Reference Example 2 was obtained by reduction of graphene oxide, when the oxygen-containing functional group on the surface of the graphene oxide was removed, part of the graphene was removed. The surface is wrinkled and disorderly stacked, and the original crystal face (002) is restored, so this characteristic peak appears, indicating that the reduced graphene oxide is indeed prepared; the JCPDS standard diffraction pattern (JCPDS 27-0050) shows that With respect to the characteristic peak of the crystal plane (201) of the diffraction peak β-Bi ₂ O ₃ of about 28° 2θ, it can be seen from Fig. 3 that the diffracted peak intensities of Examples 1 to 5 at 2θ of about 28° do follow The concentration of lanthanum nitrate used is increased; however, since the crystal plane signal of β-Bi ₂ O ₃ is relatively strong, the characteristic peak of reduced graphene oxide cannot be clearly exhibited.

分析analysis 44 ：傅立葉紅外光譜分析: Fourier infrared spectroscopy

如圖4由下至上依序為石墨片原料、參考例1、參考例2、實施例3以傅立葉紅外光譜儀分析其組成成分、分子結構及化學鍵等資訊。如圖4中的石墨片原料之測驗結果所示，由於石墨片本身具有高度穩定的化學性質，而沒有呈現明顯的吸收峰；而如圖4中的參考例1之分析結果所示，參考例1之氧化石墨烯，在1634 cm ^-1附近之吸收峰對應於OH基之彎曲振動，且在3430 cm ^-1附近出現一對應於OH之伸縮振動的吸收峰，並於3000 cm ^-1至3700 cm ^-1呈現一寬吸收峰，此為氧化石墨烯經由氧化處理後，引入的含氧官能基容易與水分子形成氫鍵所致；另外，相較於參考例1，以水熱合成法所還原而得的參考例2之還原氧化石墨烯以及實施例3之石墨烯-氧化鉍複合材料於3430 cm ^-1附近之吸收峰明顯削弱，且於1634 cm ^-1、1720 cm ^-1、1380 cm ^-1及1045 cm ^-1等代表含氧官能基吸收峰亦同時有下降的趨勢，意味著利用水熱合成法確實能成功地將含氧官能基消除，還原氧化石墨烯。 As shown in Fig. 4, the graphite composition, the reference example 1, the reference example 2, and the third embodiment were analyzed by Fourier transform infrared spectroscopy in order to analyze the composition, molecular structure and chemical bond. As shown in the test results of the graphite sheet raw material in FIG. 4, since the graphite sheet itself has highly stable chemical properties, it does not exhibit a distinct absorption peak; and as shown in the analysis result of Reference Example 1 in FIG. 4, the reference example The graphene oxide of ¹ , the absorption peak near 1634 cm ^-1 corresponds to the bending vibration of the OH group, and an absorption peak corresponding to the stretching vibration of OH appears in the vicinity of 3430 cm ^-1 , and is from 3000 cm ^-1 to 3700 Cm ^-1 exhibits a broad absorption peak, which is caused by the oxygen bond introduced by the oxidation of graphene oxide through oxidation treatment, which is easily formed by hydrogen bonding with water molecules; in addition, compared with Reference Example 1, by hydrothermal synthesis The reduced graphene oxide of Reference Example 2 and the graphene-yttria composite of Example 3 were significantly weakened at around 3430 cm ^-1 , and were at 1634 cm ^-1 , 1720 cm ^-1 , and 1380 cm . ^-1 and 1045 cm ^-1 represent the tendency of the oxygen-containing functional group absorption peak to decrease at the same time, which means that the hydrothermal synthesis method can be successfully used to eliminate the oxygen-containing functional group and reduce the graphene oxide.

分析analysis 55 ：: SEMSEM 分析analysis

參考例2及實施例1至5使用高解析場發射型掃描式電子顯微鏡(ultra-high resolution field-emission scanning electron microscope，FE-SEM)觀察該等材料的型貌。Reference Example 2 and Examples 1 to 5 were used to observe the morphology of the materials using an ultra-high resolution field-emission scanning electron microscope (FE-SEM).

如圖5A所示，參考例2之還原氧化石墨烯的部分形貌呈現出緊密堆疊狀，主要是因為原先在表面含氧官能基的被移除，而發生堆疊效應所致；請參考圖5B至圖5D之實施例1至3的SEM照片，可以發現隨著製備時所使用的氧化鉍增加，致使石墨烯表面的粗糙度也隨之提升，且實施例1至3的石墨烯層間呈現的皺摺狀及蓬鬆感程度亦隨之上升，此現象是源於氧化鉍插層於石墨烯之間的交互作用所致；隨著製備時所使用的氧化鉍更增加，因受到足夠多的氧化鉍顆粒進入石墨烯層間，因此如圖5E呈現實施例4的表面為開層片狀結構，如同剝離的效果；然而，如圖5F所示，實施例5的SEM照片呈現其表面的形貌異於前述實施例1至4，反而更接近石墨片的堆疊結構；係因煆燒過程中，當氧化鉍含量高於某一程度時，會發生明顯的團聚現象而脫離載體，因此反而失去撐擴石墨烯層間的物質，造成部分還原成石墨結構。As shown in FIG. 5A, the partial morphology of the reduced graphene oxide of Reference Example 2 exhibited a close stacking, mainly because the stacking effect was originally caused by the removal of the oxygen-containing functional groups on the surface; please refer to FIG. 5B. To the SEM photographs of Examples 1 to 3 of FIG. 5D, it was found that the roughness of the graphene surface was also increased as the cerium oxide used in the preparation was increased, and the graphene layers of Examples 1 to 3 were present. The degree of wrinkling and fluffiness also increases, which is caused by the interaction between the yttrium oxide intercalation layer and graphene; as the yttrium oxide used in the preparation increases, it is subject to sufficient oxidation. The ruthenium particles enter between the graphene layers, so that the surface of Example 4 is an open-layer sheet structure as shown in Fig. 5E, like the effect of peeling; however, as shown in Fig. 5F, the SEM photograph of Example 5 exhibits a different surface morphology. In the foregoing Embodiments 1 to 4, it is closer to the stacked structure of the graphite sheet; when the content of yttrium oxide is higher than a certain degree during the smoldering process, a significant agglomeration phenomenon occurs and leaves the carrier, thereby losing the expansion. Graphene interlayer The substance causes partial reduction to a graphite structure.

分析analysis 66 ：實施例:Example 33 之It TEMTEM 照片以及氧化鉍之電子繞射圖Photograph and electron diffraction pattern of yttrium oxide

請參考圖6，黑色顆粒(如圖6中的e)為氧化鉍之奈米粒子，其顆粒大小的尺寸介於10 nm至50 nm間；而透明皺褶狀的部分(如圖6中的d)則為還原氧化石墨烯；由圖6可以觀察到氧化鉍奈米粒子分布於石墨烯結構中，且石墨烯於含有氧化鉍處呈現出明顯的***及皺褶狀；圖7為氧化鉍顆粒之電子繞射圖，分析後得知，其符合β相之氧化鉍的晶面座標，於此可證，石墨烯-氧化鉍複合材料中含有的氧化鉍為β-Bi ₂O ₃。 Referring to Figure 6, the black particles (e in Figure 6) are cerium oxide nanoparticles with a particle size ranging from 10 nm to 50 nm; and a transparent pleated portion (as in Figure 6). d) is the reduction of graphene oxide; from Figure 6, it can be observed that the cerium oxide nanoparticles are distributed in the graphene structure, and the graphene exhibits obvious ridges and wrinkles in the presence of cerium oxide; The electron diffraction pattern of the particles is analyzed and found to be in conformity with the crystal plane coordinates of the β-phase yttrium oxide. It can be confirmed that the cerium oxide contained in the graphene-yttria composite material is β-Bi ₂ O ₃ .

分析analysis 77 ：多功能掃描探針顯微鏡分析: Multi-functional scanning probe microscopy analysis

理論上單層石墨烯的厚度為0.35 nm，但由於表面易受吸附物的影響，導致測得的厚度較理論值厚；以多功能掃描探針顯微鏡分析參考例2和實施例3的石墨烯厚度及形貌：沒有氧化鉍存在的情況下，還原的過程容易發生無序堆疊的情形，因此參考例2的石墨烯厚度約為1.1 nm至2.0 nm，層數約為2層至6層；另一方面，由於負載有氧化鉍顆粒，因此實施例3之石墨烯的厚度相較於參考例2較厚，其厚度為2 nm至4 nm，層數約為4層至8層。Theoretically, the thickness of the single-layer graphene is 0.35 nm, but the measured thickness is thicker than the theoretical value due to the surface being susceptible to the adsorbate; the graphene of Reference Example 2 and Example 3 is analyzed by a multifunctional scanning probe microscope. Thickness and morphology: in the absence of yttrium oxide, the reduction process is prone to disordered stacking, so the graphene thickness of Reference Example 2 is about 1.1 nm to 2.0 nm, and the number of layers is about 2 to 6 layers; On the other hand, since the cerium oxide particles were supported, the thickness of the graphene of Example 3 was thicker than that of Reference Example 2, and the thickness thereof was 2 nm to 4 nm, and the number of layers was about 4 to 8 layers.

分析analysis 88 ：比表面積、孔洞體積與平均孔徑分析: specific surface area, pore volume and average pore size analysis

使用比表面積分析儀(Brunauer-Emmett-Teller specific surface area and porosity analyzer, BET)量測參考例2和實施例3的比表面積、孔洞體積和平均孔徑，並將量測結果列於下表1中。 表1：參考例2和實施例3的比表面積、孔洞體積和平均孔徑 性質 參考例2 實施例3 比表面積 (m2/g) 358.9 72.04 孔洞體積 (cm3/g) 1.46 0.148 平均孔徑 (nm) 16.28 8.225 The specific surface area, pore volume and average pore diameter of Reference Example 2 and Example 3 were measured using a Brunauer-Emmett-Teller specific surface area and porosity analyzer (BET), and the measurement results are listed in Table 1 below. . Table 1: Specific surface area, pore volume and average pore diameter of Reference Example 2 and Example 3   Properties Reference Example 2 Example 3 Specific surface area (m2/g) 358.9 72.04 Hole volume (cm3/g) 1.46 0.148 Average pore diameter (nm) 16.28 8.225

由上表1可知，參考例2之還原氧化石墨烯的平均孔徑為16.28 nm，屬於中孔結構；另外，參考例2的比表面積為358.9 m ²/g，比現有技術使用有機溶劑製備的還原氧化石墨烯的比表面積(294.0 m ²/g和206.2 m ²/g)高了許多；以實施例3為例，其比表面積為72.04 m ²/g、平均孔徑為8.225 nm、以及孔體積為1.46 cm ³/g，係因還原氧化石墨烯的表面孔洞受到氧化鉍顆粒的吸附、填充所致，由此證明，本創作之製備方法確實可成功製備石墨烯-氧化鉍複合材料。 It can be seen from the above Table 1 that the reduced graphene oxide of Reference Example 2 has an average pore diameter of 16.28 nm and belongs to a mesoporous structure; in addition, the specific surface area of Reference Example 2 is 358.9 m ² /g, which is lower than that of the prior art using an organic solvent. The specific surface area (294.0 m ² /g and 206.2 m ² /g) of graphene oxide is much higher; in the case of Example 3, the specific surface area is 72.04 m ² /g, the average pore diameter is 8.225 nm, and the pore volume is 1.46 cm ³ /g, because the surface pores of the reduced graphene oxide are adsorbed and filled by cerium oxide particles, which proves that the preparation method of the present invention can successfully prepare the graphene-yttria composite material.

分析analysis 99 ：拉曼光譜分析:Raman spectroscopy

參考例1、參考例2及實施例1至5使用拉曼光譜(Raman spectroscopy)觀察該等材料中sp ²雜化碳原子面內的振動模式，並將量測結果列於下表2中。 表2：參考例1、參考例2及實施例1至5的G峰和R值 性質 參考例1 參考例2 實施例1 實施例2 G峰(cm-1) 1597.9 1585.5 1587.3 1589 R值 0.87 0.956 0.99 0.998 實施例3 實施例4 實施例5 G峰(cm-1) 1590.8 1589 1587.3 R值 1.002 1.009 1.027 Reference Example 1, Reference Example 2, and Examples 1 to 5 were observed by Raman spectroscopy in the in-plane vibration mode of sp ² hybridized carbon atoms in the materials, and the measurement results are shown in Table 2 below. Table 2: G peak and R value properties of Reference Example 1, Reference Example 2, and Examples 1 to 5 Reference Example 1 Reference Example 2 Example 1 Example 2 G peak (cm-1) 1597.9 1585.5 1587.3 1589 R value 0.87 0.956 0.99 0.998 Example 3 Example 4 Example 5 G peak (cm-1) 1590.8 1589 1587.3 R value 1.002 1.009 1.027

拉曼光譜分析係採用指紋性的振動光譜技術，對分子結構與材料成分具有高度的靈敏性。以拉曼光譜分析石墨烯時，天然石墨片在約1350 cm ^-1(D峰)附近出現一微弱的特徵峰，其對應石墨片的自然缺陷；另外，天然石墨片在約1580 cm ^-1(G峰)有一高強度且陡直的特徵峰，對應石墨片sp ²結構的特徵峰。而氧化石墨烯之拉曼光譜，則可發現D峰轉為高強度的特徵峰，而其在G峰的特徵峰則比天然石墨片的特徵峰更為寬化，其係因石墨片的規則堆疊結構，受到了含氧官能基的鍵結，致使氧化石墨烯的對稱性與結晶性下降，而導致寬化峰的出現。另外，以D峰與G峰之訊號強度比I _D/I _G，即R值，來判定還原氧化石墨烯之規則及對稱性，R值越高代表亂度愈高；且可利用G峰的位置對石墨烯層數變化非常敏感，受到石墨烯層數的多寡而位移的特性，判斷石墨烯的層數；當G峰向高波數位移，代表石墨烯層數越低。 Raman spectroscopy uses fingerprint vibrational spectroscopy to have a high sensitivity to molecular structure and material composition. When graphene is analyzed by Raman spectroscopy, the natural graphite sheet shows a weak characteristic peak near about 1350 cm ^-1 (D peak), which corresponds to the natural defect of the graphite sheet; in addition, the natural graphite sheet is about 1580 cm ^-1 ( G peak) has a high intensity and steep characteristic peak corresponding to the characteristic peak of the sp ² structure of the graphite sheet. The Raman spectrum of graphene oxide can be found that the D peak turns into a high-intensity characteristic peak, and its characteristic peak at the G peak is wider than the characteristic peak of the natural graphite sheet, which is due to the rule of the graphite sheet. The stacked structure is bonded by an oxygen-containing functional group, resulting in a decrease in the symmetry and crystallinity of the graphene oxide, resulting in the appearance of a broadening peak. In addition, the signal intensity ratio I _D /I _{G of the} D peak and the G peak, that is, the R value, is used to determine the regularity and symmetry of the reduced graphene oxide. The higher the R value, the higher the disorder, and the position of the G peak can be utilized. It is very sensitive to the change of graphene layer number, and it is judged by the characteristics of the number of graphene layers and the displacement of the graphene layer. When the G peak shifts to the high wavenumber, it means that the graphene layer number is lower.

參考例1的R值為0.87，代表其具有更高的規則性與較低的亂度，而其G峰位於1597.9 cm ^-1這印證了氧化石墨烯引入的含氧官能基確實能將石墨片的層間距離撐開，而破壞其層間結構；而以水熱合成法還原製備的參考例2，由於消除含氧官能基，導致其sp ²結構堆疊程度上升，還原成石墨片的機率增加，致使G峰向低波數位移而出現在1585.5 cm ^-1。從實施例1至5可知，隨著添加硝酸鉍的含量增加，R值亦有提升之趨勢，這是由於負載的氧化鉍顆粒，間接影響了石墨烯表面與層間距的規則性，進而導致石墨烯結構排列的亂度增加。此外，因以煆燒的方式合成石墨烯-氧化鉍複合材料，因此當氧化鉍濃度提升至一定程度時，煆燒的過程會使得氧化鉍團聚而脫離石墨烯載體，導致該等複合材料中的石墨烯無法穩定維持石墨烯態，而部分還原為石墨，使G峰因此上升。 The R value of Reference Example 1 is 0.87, which means that it has higher regularity and lower chaos, and its G peak is located at 1597.9 cm ^{-1 ,} which confirms that the oxygen-containing functional group introduced by graphene oxide can actually produce graphite flakes. The interlayer distance is expanded to destroy the interlayer structure; and the reference example 2 prepared by hydrothermal synthesis reduction, due to the elimination of the oxygen-containing functional group, leads to an increase in the degree of sp ² structure stacking, and the probability of reduction into graphite sheets is increased, resulting in an increase in the interlayer distance. The G peak appears at 1585.5 cm ^-1 to the low wavenumber displacement. It can be seen from Examples 1 to 5 that as the content of lanthanum nitrate added increases, the R value also increases. This is because the supported cerium oxide particles indirectly affect the regularity of the surface distance between the graphene and the layer, which leads to graphite. The disorder of the structure of the olefin structure increases. In addition, since the graphene-yttria composite is synthesized by calcination, when the concentration of cerium oxide is increased to a certain extent, the calcination process causes the cerium oxide to agglomerate and leave the graphene carrier, resulting in the composite material. Graphene cannot stably maintain the graphene state, but is partially reduced to graphite, so that the G peak is thus increased.

分析analysis 1010 ：熱重力分析: Thermal Gravity Analysis

在空氣的氣氛下，以10°C/分的速度升溫至800°C，利用熱分析儀檢測參考例1、參考例2、實施例3的熱重力分析，以探討其裂解溫度、熱穩定性、成分比例、還原溫度及抗氧化性等特性。對參考例1之氧化石墨烯而言，於約100°C時有部分的熱損失，主要是氧化石墨烯層間吸收的水分移除，約為15重量%；而在約200°C時的熱損失，為氧化石墨烯之含氧官能基受到熱處理而脫除；另外，參考例1於升溫的過程中發生熱還原而使石墨烯團聚成石墨態的比例增加，導致碳之分解溫度提高至約590°C。而對於參考例2之還原氧化石墨烯，主要熱分解有兩階段，第一階段為約100°C時的水分移除；另一階段為490°C的石墨烯熱分解，相較於參考例1，參考例2之碳的分解溫度下降，表示以水熱合成法還原的石墨烯具有更高的石墨烯含量。對於實施例3之複合材料，主要的熱分解階段包括約160°C時出現的熱損失，應係由於製備過程中，以氨水調配溶液酸鹼值時形成的硝酸銨副產物之熱分解；接著是約400°C時石墨烯的熱裂解，由於其層間結構中受到氧化鉍顆粒的剝層，使得石墨烯團聚成石墨的比例下降，而具有更高純度的還原氧化石墨烯，致使其碳分解溫度最低，最後達穩定態，剩餘28重量%的物質，應為氧化鉍的重量。由此可證，本創作確實合成出石墨烯-氧化鉍複合材料。The temperature was raised to 800 ° C at a rate of 10 ° C / min in an air atmosphere, and the thermal gravimetric analysis of Reference Example 1, Reference Example 2, and Example 3 was examined by a thermal analyzer to investigate the cracking temperature and thermal stability. Characteristics such as composition ratio, reduction temperature and oxidation resistance. For the graphene oxide of Reference Example 1, there is a partial heat loss at about 100 ° C, mainly due to moisture absorption between the layers of graphene oxide, about 15% by weight; and heat at about 200 ° C. The loss is that the oxygen-containing functional group of the graphene oxide is removed by heat treatment; in addition, the proportion of the graphene agglomerated into a graphite state is increased by thermal reduction in the heating process of Reference Example 1, resulting in an increase in the decomposition temperature of carbon to about 590 ° C. For the reduced graphene oxide of Reference Example 2, there are two stages of main thermal decomposition, the first stage is moisture removal at about 100 ° C; the other stage is thermal decomposition of graphene at 490 ° C, compared to the reference example. 1. The decomposition temperature of carbon of Reference Example 2 decreased, indicating that graphene reduced by hydrothermal synthesis has a higher graphene content. For the composite of Example 3, the main thermal decomposition stage includes the heat loss occurring at about 160 ° C, which is due to the thermal decomposition of the ammonium nitrate by-product formed by the ammonia water solution during the preparation process; It is the thermal cracking of graphene at about 400 ° C. Due to the delamination of cerium oxide particles in the interlayer structure, the proportion of graphene aggregated into graphite decreases, and the reduced graphene oxide with higher purity causes the carbon to decompose. The temperature is the lowest, and finally reaches a steady state, and the remaining 28% by weight of the substance should be the weight of cerium oxide. It can be proved that this creation does synthesize a graphene-yttria composite.

製備參考例Preparation reference example 33 、參考例Reference example 44 、實施例Example 66 至to 1010 之電極材料Electrode material

將參考例1之氧化石墨烯、參考例2之還原氧化石墨烯、實施例1至5之石墨烯-氧化鉍複合材料分別磨成粉末後，各自與作為黏著劑之聚四氟乙烯、碳黑以8：1：1之重量比研磨均勻，倒入小型樣品瓶中，滴加數滴無水乙醇，進行超音波震盪30分鐘後，使樣品混合均勻，再以滴管吸取溶液，滴加於經拋光、去汙處理的石墨片上使其自然分散，最後，置於80°C烘箱乾燥，得到參考例3、參考例4、實施例6至10之電極材料。The graphene oxide of Reference Example 1, the reduced graphene oxide of Reference Example 2, and the graphene-yttria composite materials of Examples 1 to 5 were respectively ground into powder, and each of them was used as a polytetrafluoroethylene or carbon black as an adhesive. Grind evenly at a weight ratio of 8:1:1, pour into a small sample vial, add a few drops of absolute ethanol, perform ultrasonic vibration for 30 minutes, mix the sample evenly, then draw the solution with a dropper and add it to the solution. The polished and decontaminated graphite sheets were naturally dispersed, and finally dried in an oven at 80 ° C to obtain electrode materials of Reference Example 3, Reference Example 4, and Examples 6 to 10.

分析analysis 1111 ：電化學特性分析: Electrochemical characteristics analysis

使用三極法進行以下電化學特性測試：使用銀/氯化銀作為參考電極，4平方公分的白金片為對應電極，以及分別由參考例3、參考例4、實施例6至10之電極材料做為工作電極。The following electrochemical characteristics test was carried out using a three-pole method: silver/silver chloride was used as a reference electrode, a 4 cm-cm white gold plate was used as a counter electrode, and electrode materials of Reference Example 3, Reference Example 4, and Examples 6 to 10, respectively. As a working electrode.

(1)(1) 循環伏安法分析Cyclic voltammetry analysis

分別對參考例3之電極材料、參考例4之電極材料，以及實施例6至10的電極材料以10 mV/s的掃描速率做循環伏安法分析。如圖8的參考例3之C-V特性曲線，其近似於矩形，且無明顯的氧化還原趨勢，係典型的電容行為；如圖8的參考例4之C-V特性曲線，其曲線的形狀與參考例3的曲線形狀相似，但曲線面積較大，掃描速率提升時能維持一定的曲線穩定；從實施例6至10的電極材料之循環伏安法分析結果顯示，隨著氧化鉍濃度的提升，曲線形狀仍保持一定的矩形，但具有愈來愈高的曲線面積，以實施例10為例，如圖8中實施例10的C-V特性曲線所示，其曲線面積明顯大於參考例3和參考例4的曲線面積。The electrode material of Reference Example 3, the electrode material of Reference Example 4, and the electrode materials of Examples 6 to 10 were subjected to cyclic voltammetry analysis at a scanning rate of 10 mV/s, respectively. The CV characteristic curve of Reference Example 3 of FIG. 8 is approximately rectangular, and has no obvious redox tendency, and is a typical capacitive behavior; the CV characteristic curve of Reference Example 4 of FIG. 8 has a curve shape and a reference example. The shape of the curve of 3 is similar, but the curve area is large, and the curve is stable when the scanning rate is increased; the cyclic voltammetry analysis of the electrode materials of Examples 6 to 10 shows that as the concentration of cerium oxide increases, the curve The shape still maintains a certain rectangle, but has an increasingly higher curved area. Taking Embodiment 10 as an example, as shown in the CV characteristic curve of Embodiment 10 in FIG. 8, the curve area is significantly larger than that of Reference Example 3 and Reference Example 4. The area of the curve.

(2)(2) 充、放電性能Charge and discharge performance 分析analysis

以1 A/g的測試條件對該等電極材料進行充、放電測試。由圖9中參考例3的充、放電測試結果得知，其僅具有50法拉/克(F/g)之電容值。如圖9中參考例4的充、放電測試結果得知，其電容值則為84.6 F/g，雖然其缺乏了能穩定石墨烯之因子，造成石墨烯中部分的sp ²結構團聚，但其電容值仍高於參考例3的電極表現。隨著氧化鉍的濃度增加，參考例6至10的電容值亦增加，其中，以參考例10的充、放電測試結果為例，圖9中參考例10之充、放電測試結果，其電容值為196 F/g，明顯大於參考例3和參考例4的電容值。 The electrode materials were tested for charge and discharge at a test condition of 1 A/g. From the results of the charge and discharge tests of Reference Example 3 in Fig. 9, it was found that it had only a capacitance value of 50 Farads/gram (F/g). As shown in the charge and discharge test results of Reference Example 4 in FIG. 9, the capacitance value is 84.6 F/g. Although it lacks a factor capable of stabilizing graphene, causing partial sp ² structure agglomeration in graphene, The capacitance value is still higher than that of Reference Example 3. As the concentration of yttrium oxide increases, the capacitance values of Reference Examples 6 to 10 also increase, wherein the charge and discharge test results of Reference Example 10 are taken as an example, and the charge and discharge test results of Reference Example 10 in FIG. 9 have capacitance values. It is 196 F/g, which is significantly larger than the capacitance values of Reference Example 3 and Reference Example 4.

(3)(3) 循環壽命分析Cycle life analysis

如圖10所示，實施例8的電極材料經由3000圈的充、放電測試，仍能有99.6%的電容保持率，由此可知石墨烯-氧化鉍複合材料具有良好的可逆性。另外，同時由圖10可得知，實施例8的電極材料經由3000圈的充、放電測試，仍能維持98%的庫侖效率，顯示本創作的電極材料對於電子的吸附、脫離具有良好的可逆性，亦能維持電容穩定性。As shown in FIG. 10, the electrode material of Example 8 can still have a capacitance retention rate of 99.6% through the charge and discharge test of 3000 cycles, and thus it is known that the graphene-yttria composite material has good reversibility. In addition, as can be seen from FIG. 10, the electrode material of Example 8 can maintain a coulombic efficiency of 98% through the charge and discharge test of 3000 cycles, and shows that the electrode material of the present invention has good reversibility for electron adsorption and detachment. Sexuality also maintains capacitance stability.

(4)(4) 電化學阻抗頻譜Electrochemical impedance spectrum (electrochemistry impedance spectroscopyElectrochemistry impedance spectroscopy ，, EIS)EIS) 分析analysis

由交流阻抗數據可模擬電極之等效電路圖，用以計算相應的電極反應參數。理論而言，EIS於低頻部分的發散區段，延伸至X軸(Z' (Ω))之截距，所圍之高頻區段，可視為測試元件之總阻抗(R _t)，而元件總阻抗(R _t)為三阻抗之和，以下列表示：R _t= R _s+ R _c+ R _p；分別為電解液之離子移動阻抗(R _s)、電荷轉移阻抗(R _c)及離子移動之質傳阻抗(R _p)。將參考例4及實施例8之電極材料的交流阻抗分析結果如圖11所呈現，並將計算而得的各阻抗參數列於下表3。由圖11的結果可知，實施例8所形成的曲線於高頻的部分具有較小的半圓直徑，其表示實施例8之R _c阻抗低，電荷轉移能力佳；並且，由圖11可知，實施例8的所形成的曲線具有大於45°之斜直線，代表其具有優異的電容性質。另外，由下表3可知，實施例8之電極材料具有更低的R _s阻抗，這可歸因於石墨烯負載氧化鉍顆粒，其能有效的剝離石墨烯進而提升電解液與電極材料間浸潤的程度。 表3：參考例4和實施例8的電極阻抗數值分析結果 Rt Rs Rc Rp 參考例4之阻抗 (Ω) 6.61 1.77 3.78 1.06 實施例8之阻抗 (Ω) 2.34 1.20 0.52 0.62 The equivalent circuit diagram of the electrode can be simulated from the AC impedance data to calculate the corresponding electrode reaction parameters. Theoretically, the divergence section of the EIS in the low frequency part extends to the intercept of the X-axis (Z' (Ω)), and the high-frequency section enclosed can be regarded as the total impedance (R _t ) of the test component, and the component The total impedance (R _t ) is the sum of the three impedances, expressed as follows: R _t = R _s + R _c + R _p ; respectively, the ion mobility resistance (R _s ), charge transfer impedance (R _c ), and ion of the electrolyte The mass transfer impedance (R _p ) of the movement. The results of the AC impedance analysis of the electrode materials of Reference Example 4 and Example 8 are shown in Fig. 11, and the calculated impedance parameters are shown in Table 3 below. As is clear from the results of FIG. 11, the curve formed in Example 8 has a small semicircular diameter at a portion having a high frequency, which indicates that the R _c impedance of Example 8 is low, and the charge transfer ability is good; and, as apparent from FIG. The resulting curve of Example 8 has a diagonal line greater than 45°, indicating that it has excellent capacitive properties. In addition, as can be seen from Table 3 below, the electrode material of Example 8 has a lower R _s impedance, which can be attributed to the graphene-supported cerium oxide particles, which can effectively strip the graphene and thereby enhance the infiltration between the electrolyte and the electrode material. Degree. Table 3: Electrode impedance numerical analysis results of Reference Example 4 and Example 8 Rt Rs Rc Rp Impedance (Ω) of Reference Example 6.61 1.77 3.78 1.06 Impedance (Ω) of Example 8 2.34 1.20 0.52 0.62

實驗結果討論Discussion of experimental results

從圖3之XRD分析可知，本創作實施例1至5的石墨烯-氧化鉍複合材料具有純淨度更高的特徵峰表徵，其係因實施例1至5係採用兩階段煆燒，因此能獲得晶型一致性高的結果。It can be seen from the XRD analysis of FIG. 3 that the graphene-yttria composite materials of the present inventive examples 1 to 5 have a characteristic peak with higher purity, which is because the two-stage calcination is used in the examples 1 to 5, The result of high crystal form consistency is obtained.

比較圖5A至圖5F的SEM結果可以看出，圖5B至圖5F的實施例1至5之石墨烯-氧化鉍複合材料因氧化鉍顆粒插層於石墨烯層之間，而非聚集於石墨烯表面，使得石墨烯層的表面型態與先前技術的玫瑰花瓣形貌不同，反而呈現出似於紫菜狀的形貌，其具有較多的皺摺狀及蓬鬆感程度上升，可提供本創作的石墨烯-氧化鉍複合材料的再負載及再添加的可行性。Comparing the SEM results of FIGS. 5A to 5F, it can be seen that the graphene-yttria composite materials of Examples 1 to 5 of FIGS. 5B to 5F are intercalated between the graphene layers by the cerium oxide particles instead of being aggregated in the graphite. The surface of the eneene makes the surface morphology of the graphene layer different from that of the prior art rose petal, but instead appears like a laver-like morphology, which has more wrinkles and a higher degree of fluffiness, which can provide the creation. Feasibility of reloading and re-adding graphene-yttria composites.

從圖8的循環伏安法曲線圖可知，參考例3和參考例4之電極材料的分析結果呈現類似矩形的形狀，無明顯的氧化還原趨勢，屬於典型的電容行為；但參考例3之電極材料包含氧化石墨烯，因石墨烯層間與表面引入有大量含氧官能基，使得導電性降低，且其具有的親水特性恐會使電極於水系之電解液中逐漸崩塌而出現不穩定現象；而參考例4之電極材料因包含還原氧化石墨烯，因此石墨烯之表面含氧官能基降低，而殘存的少部分可活化之含氧官能基會提升電極與電解液間的浸潤程度，進而提高導電性能，不過，主要仍以電雙層作為儲能機制；而由本創作之電極材料的分析結果可知，因其曲線面積大於參考例3和參考例4的曲線面積，證明本創作的石墨烯-氧化鉍複合材料有助於提升電極材料的導電性，更能提升電極材料的電荷儲存效果。It can be seen from the cyclic voltammetry graph of FIG. 8 that the analysis results of the electrode materials of Reference Example 3 and Reference Example 4 exhibit a rectangular-like shape without a significant redox tendency, which is a typical capacitive behavior; however, the electrode of Reference Example 3 The material contains graphene oxide, and a large amount of oxygen-containing functional groups are introduced between the layers and the surface of the graphene, so that the conductivity is lowered, and the hydrophilic property thereof may cause the electrode to gradually collapse in the water-based electrolyte to cause instability; The electrode material of Reference Example 4 contains reduced graphene oxide, so that the surface oxygen-containing functional group of the graphene is lowered, and a small portion of the activated oxygen-containing functional group remains to promote the degree of infiltration between the electrode and the electrolyte, thereby improving conductivity. Performance, however, mainly uses the electric double layer as the energy storage mechanism; and the analysis result of the electrode material of the present invention shows that the graphene-oxidation of the present invention is proved because the curve area is larger than the curved area of Reference Example 3 and Reference Example 4. The ruthenium composite material helps to improve the conductivity of the electrode material and enhance the charge storage effect of the electrode material.

從圖9的充、放電曲線圖可知，參考例3的電極材料因其包含的石墨烯表面存在大量的含氧官能基，使導電性較參考例4的電極材料低，進而使電容值也較參考例4的電極材料小；而本創作的電極材料，因包含本創作的石墨烯-氧化鉍複合材料，由於氧化鉍擴充了石墨烯層間的距離，不僅提高了電荷儲存能力，氧化鉍也同時可供應擬電容，因此，使本創作的電極材料能提供更高的能量容量。As can be seen from the charge and discharge graphs of FIG. 9, the electrode material of Reference Example 3 has a large amount of oxygen-containing functional groups on the surface of the graphene contained therein, so that the conductivity is lower than that of the electrode material of Reference Example 4, and the capacitance value is also improved. The electrode material of the reference example 4 is small; and the electrode material of the present invention contains the graphene-yttria composite material of the present invention, since the yttrium oxide expands the distance between the graphene layers, not only the charge storage capacity is improved, but also the yttrium oxide is simultaneously The pseudo-capacitor can be supplied, thus enabling the electrode material of the present invention to provide a higher energy capacity.

從電化學特性分析的結果可知，本創作的電極材料具有電容保持率高、總阻抗低、質傳性能良好等電性特質，證明本創作的電極材料能適用於超級電容器。From the results of electrochemical analysis, the electrode material of the present invention has high electrical conductivity, low total impedance, good quality and good electrical properties, which proves that the electrode material of the present invention can be applied to supercapacitors.

上述實施例僅係為了方便說明而舉例而已，惟該實施方式並非用以限定本創作之申請專利範圍；任何所屬技術領域中具有通常知識者，在不脫離本創作技術方案的範圍內，當可利用上述揭示的技術內容做出些許更動或修飾為等同變化的等效實施例，但凡是未脫離本創作之技術方案的內容，依據本創作的技術實質對以上實施例作任何簡單修改、等同變化與修改，均仍屬於本創作技術方案的範圍內。The above-mentioned embodiments are merely examples for the convenience of the description, but the embodiments are not intended to limit the scope of the patent application of the present invention; any one of ordinary skill in the art may, without departing from the scope of the present invention, The equivalents of the above-described technical solutions are used to make any modifications or equivalent changes to the equivalent embodiments. However, any changes and equivalents to the above embodiments may be made in accordance with the technical essence of the present invention without departing from the technical scope of the present invention. And the modifications are still within the scope of this creative technical solution.

無。no.

圖1係製備例1、石墨片原料(325 mesh)的X射線繞射圖譜及石墨片的標準繞射圖譜。 圖2A和圖2B分別為石墨片和製備例1之電子繞射圖。 圖3係參考例2、實施例1至5的X射線繞射圖譜。 圖4係石墨片原料、參考例1、參考例2、實施例3的紅外光譜圖譜。 圖5A至5F分別為參考例2、實施例1至5的FE-SEM照片。 圖6係實施例3的TEM照片。 圖7係實施例3中氧化鉍的電子繞射圖。 圖8係參考例3、參考例4和實施例10的循環伏安曲線圖。 圖9係參考例3、參考例4和實施例10的充、放電曲線圖。 圖10係實施例8經由3000圈的充、放電測試之循環壽命分析圖。 圖11係參考例4及實施例8的交流阻抗分析圖。Figure 1 is a schematic diagram of the X-ray diffraction pattern of the graphite sheet material (325 mesh) and the standard diffraction pattern of the graphite sheet. 2A and 2B are an electron diffraction diagram of a graphite sheet and Preparation Example 1, respectively. 3 is an X-ray diffraction pattern of Reference Example 2 and Examples 1 to 5. 4 is an infrared spectrum spectrum of a graphite sheet raw material, Reference Example 1, Reference Example 2, and Example 3. 5A to 5F are FE-SEM photographs of Reference Example 2 and Examples 1 to 5, respectively. Fig. 6 is a TEM photograph of Example 3. Figure 7 is an electron diffraction pattern of cerium oxide in Example 3. 8 is a cyclic voltammogram of Reference Example 3, Reference Example 4, and Example 10. Fig. 9 is a graph showing charging and discharging curves of Reference Example 3, Reference Example 4, and Example 10. Fig. 10 is a cycle life analysis chart of the charge and discharge test of Example 8 via 3000 cycles. 11 is an AC impedance analysis diagram of Reference Example 4 and Example 8.

無。no.

Claims (7)

一種石墨烯-氧化鉍複合材料的製備方法，包括以下步驟：步驟(a)：製備氧化石墨烯水溶液；步驟(b)：混合該氧化石墨烯水溶液和硝酸鉍水溶液，在溫度為150℃至250℃、壓力為0.5百萬帕至1.5百萬帕進行水熱反應，以得到還原氧化石墨烯-氧化鉍的前驅物；步驟(c1)：在氮氣環境中，將該前驅物以400℃至500℃煆燒，得到一粗產物；以及步驟(c2)：在空氣環境中，將該粗產物以280℃至330℃煆燒，得到該石墨烯-氧化鉍複合材料；其中，該步驟(b)中的氧化石墨烯和硝酸鉍之固體重量比介於1：0.1至1：1.2。 A method for preparing a graphene-yttria composite material, comprising the steps of: step (a): preparing an aqueous graphene oxide solution; and step (b): mixing the aqueous graphene oxide solution and an aqueous solution of rhodium nitrate at a temperature of 150 ° C to 250 Hydrothermal reaction at a pressure of 0.5 MPa to 1.5 MPa to obtain a precursor of reduced graphene oxide-yttria; step (c1): in a nitrogen atmosphere, the precursor is 400 ° C to 500 And calcining to obtain a crude product; and step (c2): calcining the crude product at 280 ° C to 330 ° C in an air atmosphere to obtain the graphene-yttria composite material; wherein, the step (b) The solid weight ratio of graphene oxide to cerium nitrate is between 1:0.1 and 1:1.2. 如請求項1所述之製備方法，其中，該步驟(b)中，以pH值為大於或等於8，且小於10的條件下，進行水熱反應。 The preparation method according to claim 1, wherein in the step (b), the hydrothermal reaction is carried out under the condition that the pH is greater than or equal to 8, and less than 10. 如請求項1所述之製備方法，其中，該步驟(a)包括：步驟(a1)：將石墨片加入一含硫酸和磷酸的混合酸液中，得到一石墨片溶液；步驟(a2)：該石墨片溶液於溫度5℃至50℃下加入過錳酸鉀後，進行超音波震盪，得到一混合溶液；步驟(a3)：於溫度40℃至120℃下，持續攪拌該混合溶液1小時至24小時；步驟(a4)：冷卻該混合溶液的溫度至-5℃至20℃後加入雙氧水，再經過離心、乾燥步驟，得到氧化石墨烯固體；以及步驟(a5)：將該氧化石墨烯固體與水混合，以得到該氧化石墨烯水溶液。 The preparation method according to claim 1, wherein the step (a) comprises: step (a1): adding a graphite sheet to a mixed acid solution containing sulfuric acid and phosphoric acid to obtain a graphite sheet solution; and step (a2): The graphite sheet solution is subjected to ultrasonic vibration after adding potassium permanganate at a temperature of 5 ° C to 50 ° C to obtain a mixed solution; and step (a3): continuously stirring the mixed solution at a temperature of 40 ° C to 120 ° C for 1 hour. Up to 24 hours; step (a4): cooling the temperature of the mixed solution to -5 ° C to 20 ° C, adding hydrogen peroxide, passing through a centrifugation, drying step to obtain a graphene oxide solid; and step (a5): the graphene oxide The solid is mixed with water to obtain the aqueous graphene oxide solution. 一種石墨烯-氧化鉍複合材料，其係由請求項1至3中任一項所述的製備方法製備而得，該石墨烯-氧化鉍複合材料中包含複數氧化鉍顆粒及複數石墨烯層，該等氧化鉍顆粒分佈於該等石墨烯層之間，該複合材料中的比表面積介於50平方米/克至350平方米/克。 A graphene-yttria composite material obtained by the preparation method according to any one of claims 1 to 3, wherein the graphene-yttria composite material comprises a plurality of cerium oxide particles and a plurality of graphene layers. The cerium oxide particles are distributed between the graphene layers, and the specific surface area in the composite material is from 50 square meters / gram to 350 square meters / gram. 一種電極材料，包含如請求項4之石墨烯-氧化鉍複合材料。 An electrode material comprising the graphene-yttria composite material of claim 4. 如請求項5所述之電極材料，其經由3000圈的充、放電測試，電容量能維持在90%以上。 The electrode material according to claim 5, which is capable of maintaining a capacitance of 90% or more via a charge and discharge test of 3000 cycles. 一種超級電容器，包含如請求項5之電極材料。A supercapacitor comprising the electrode material of claim 5.