TW201836976A - A material preparation method for photocatalytic hydrogen production via wastewater splitting - Google Patents
A material preparation method for photocatalytic hydrogen production via wastewater splitting Download PDFInfo
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本發明係關於光觸媒的技術領域，特別是指一種使用包含石墨烯的光觸媒作為製氫材料的產氫材料製備方法及其用於有機廢水產氫的方法。The present invention relates to the technical field of photocatalyst, and more particularly to a method for preparing a hydrogen producing material using a photocatalyst comprising graphene as a hydrogen producing material and a method for producing hydrogen from an organic wastewater.
氫氣是一種清淨、高效、可再生的能源。近年來，利用半導體光催化劑光解水製氫及降解有機物等相關研究得到快速發展。在眾多的半導體光催化劑中，TiO2 因具有光催化活性高、無毒、價廉、光穩定性好等優點，成為光催化製氫首選的光催化劑。但是，純TiO2 被用作光催化劑有兩個明顯的缺點：一是帶隙較寬，只能吸收波長小於387nm的光子；二是光生電子與空穴複合率高，直接導致了其量子產率低、光催化效率低等問題，嚴重限制了TiO2 的實際應用。Hydrogen is a clean, efficient, renewable energy source. In recent years, research on the use of semiconductor photocatalysts for photolysis of water to produce hydrogen and degradation of organic matter has been rapidly developed. Among many semiconductor photocatalysts, TiO 2 has the advantages of high photocatalytic activity, non-toxicity, low cost, good light stability, etc., and has become the preferred photocatalyst for photocatalytic hydrogen production. However, the use of pure TiO 2 as a photocatalyst has two distinct disadvantages: one is that the band gap is wide, and only photons with a wavelength of less than 387 nm can be absorbed; the second is that the recombination rate of photogenerated electrons and holes is high, which directly leads to its quantum yield. The low rate and low photocatalytic efficiency severely limit the practical application of TiO 2 .
有鑑於上述技術問題，本發明提供一種產氫材料製備方法及其產物用於有機廢水產氫的方法，通過貴金屬鉑金與導電能力強的非金屬材料石墨烯對TiO2 進行改性，得到複合光觸媒，用以提高光催化產氫效率，進而將該複合光觸媒加入到含有機物之廢水作為犧牲劑參與光催化反應，同時可產氫與降解污染物。In view of the above technical problems, the present invention provides a method for preparing a hydrogen-producing material and a product thereof for producing hydrogen in an organic wastewater, and modifying the TiO 2 by a noble metal platinum and a non-metallic material graphene having strong conductivity to obtain a composite photocatalyst. In order to improve the photocatalytic hydrogen production efficiency, the composite photocatalyst is added to the wastewater containing organic matter as a sacrificial agent to participate in the photocatalytic reaction, and at the same time, hydrogen can be produced and the pollutants can be degraded.
為達前述目的，本發明提供一種氧化石墨烯的製備方法的實施例，其方法步驟包括：To achieve the foregoing objective, the present invention provides an embodiment of a method for preparing graphene oxide, the method steps of which include:
將重量比為2 ~ 1的石墨和硝酸鈉溶於濃硫酸中，再緩慢加入過錳酸鉀；Dissolving graphite and sodium nitrate in a weight ratio of 2 ~ 1 in concentrated sulfuric acid, and slowly adding potassium permanganate;
使反應在 0 ~ 5 ℃的環境溫度中持續反應；The reaction is allowed to continue at an ambient temperature of 0 to 5 ° C;
升溫至35℃，並在維持在30~35℃的環境溫度中進行攪拌；Heating to 35 ° C, and stirring at an ambient temperature maintained at 30 ~ 35 ° C;
滴加去離子水進行稀釋；Dilute deionized water to dilute;
升溫至95℃，並維持在90~95℃的環境溫度中進行攪拌；Raise to 95 ° C, and maintain stirring at an ambient temperature of 90 ~ 95 ° C;
加入去離子水後攪拌，並快速滴加過氧化氫；After adding deionized water, stirring, and rapidly adding hydrogen peroxide;
將前述反應獲得的產物進行離心、洗滌後乾燥，以獲得氧化石墨烯。The product obtained by the foregoing reaction was centrifuged, washed, and dried to obtain graphene oxide.
其中，本發明氧化石墨烯的製備方法的實施例中，石墨和硝酸鈉的重量比為2：1。Among them, in the embodiment of the method for producing graphene oxide of the present invention, the weight ratio of graphite to sodium nitrate is 2:1.
本發明進一步提供一種石墨烯改質二氧化鈦光觸媒的水熱法製備方法，其方法步驟包括：The invention further provides a hydrothermal preparation method of graphene modified titanium dioxide photocatalyst, the method steps comprising:
稱取如前所述的氧化石墨烯的製備方法製得的氧化石墨烯，並溶於去離子水中；Weigh graphene oxide prepared by the method for preparing graphene oxide as described above, and dissolve in deionized water;
攪拌後進行超聲處理；After stirring, ultrasonic treatment;
將二氧化鈦加入上述溶液中；石墨烯（GN）與二氧化鈦（TiO2 ）的含量比例為X wt% GN/ TiO2 ，其中，X＝5~20；Adding titanium dioxide to the above solution; the ratio of graphene (GN) to titanium dioxide (TiO 2 ) is X wt% GN / TiO 2 , wherein X = 5 ~ 20;
將前述混合物進行超聲處理以形成均勻分散的懸浮液；The foregoing mixture is sonicated to form a uniformly dispersed suspension;
將懸浮液置於高壓釜中，並加熱至環境溫度120℃後維持；The suspension was placed in an autoclave and heated to an ambient temperature of 120 ° C to maintain;
將前述反應獲得的產物進行過濾、洗滌後乾燥，以獲得石墨烯改質二氧化鈦光觸媒（GN/TiO2 光觸媒）。The product obtained by the foregoing reaction was filtered, washed, and dried to obtain a graphene-modified titanium dioxide photocatalyst (GN/TiO 2 photocatalyst).
其中，本發明石墨烯改質二氧化鈦光觸媒的水熱法製備方法的實施例中，石墨烯（GN）與二氧化鈦（TiO2 ）的含量比例為X wt% GN/ TiO2 ，其中X wt% GN/ TiO2 是由下式計算獲得：Wherein, in the embodiment of the hydrothermal preparation method of the graphene-modified titanium dioxide photocatalyst of the present invention, the content ratio of graphene (GN) to titanium dioxide (TiO 2 ) is X wt% GN / TiO 2 , wherein X wt% GN / TiO 2 is calculated by the following formula:
，X＝5、10、15、20。 , X = 5, 10, 15, 20
本發明進一步提供一種鉑金與石墨烯改質二氧化鈦光觸媒的光沉積法製備方法，其方法步驟包括：The invention further provides a photodeposition method for preparing platinum and graphene modified titanium dioxide photocatalyst, the method steps comprising:
稱取如前所述的石墨烯改質二氧化鈦光觸媒的水熱法製備方法製得的石墨烯二氧化鈦光觸媒，並溶於去離子水中；The graphene titanium dioxide photocatalyst prepared by the hydrothermal preparation method of the graphene-modified titanium dioxide photocatalyst as described above is weighed and dissolved in deionized water;
進行攪拌、曝氣以減少前述溶液中的溶解氧；Stirring and aeration to reduce dissolved oxygen in the aforementioned solution;
將H2 PtCl6 ‧6H2 O的甲醇溶液添加至前述溶液中，並持續曝氣；Adding a methanol solution of H 2 PtCl 6 ‧6H 2 O to the aforementioned solution, and continuing to aerate;
以紫外光在曝氣過程中及之後持續照射前述溶液；The above solution is continuously irradiated with ultraviolet light during and after the aeration;
將前述反應獲得的產物進行過濾、乾燥後煆燒，以獲得鉑金石墨烯改質二氧化鈦光觸媒（Pt-GN/ TiO2 光觸媒）；該Pt-GN/ TiO2 光觸媒上的鉑金（Pt）與二氧化鈦（TiO2 ）的含量比例為X wt% Pt-GN/ TiO2 ，其中，X wt% Pt-GN/ TiO2 是由下式計算獲得：The product obtained by the foregoing reaction is filtered, dried, and calcined to obtain a platinum-plated graphene-modified titanium dioxide photocatalyst (Pt-GN/TiO 2 photocatalyst); platinum (Pt) and titanium dioxide on the Pt-GN/TiO 2 photocatalyst ( The content ratio of TiO 2 ) is X wt% Pt-GN/TiO 2 , wherein X wt% Pt-GN/TiO 2 is calculated by the following formula:
，X＝0.1~2.0。 , X = 0.1~2.0.
其中，本發明氧化石墨烯的製備方法的實施例中，X＝5、10、15、20。In the examples of the method for producing graphene oxide of the present invention, X = 5, 10, 15, and 20.
本發明進一步提供一種鉑金改質二氧化鈦光觸媒的光沉積法製備方法，其方法步驟包括：The invention further provides a photodeposition method for preparing a platinum-modified titanium dioxide photocatalyst, the method steps comprising:
稱取二氧化鈦並溶於去離子水中；Weigh titanium dioxide and dissolve in deionized water;
進行攪拌、曝氣以減少前述溶液中的溶解氧；Stirring and aeration to reduce dissolved oxygen in the aforementioned solution;
將H2 PtCl6 ‧6H2 O的甲醇溶液添加至前述溶液中，並持續曝氣；Adding a methanol solution of H 2 PtCl 6 ‧6H 2 O to the aforementioned solution, and continuing to aerate;
以紫外光在曝氣過程中及之後持續照射前述溶液；The above solution is continuously irradiated with ultraviolet light during and after the aeration;
將前述反應獲得的產物進行過濾、乾燥後煆燒，以獲得鉑金改質二氧化鈦光觸媒（Pt- TiO2 光觸媒）；該Pt- TiO2 光觸媒上的鉑金（Pt）與二氧化鈦（TiO2 ）的含量比例為X wt% Pt- TiO2 ，其中，X wt% Pt- TiO2 是由下式計算獲得：The product obtained by the foregoing reaction is filtered, dried, and calcined to obtain a platinum-modified titanium dioxide photocatalyst (Pt-TiO 2 photocatalyst); the ratio of platinum (Pt) to titanium dioxide (TiO 2 ) on the Pt-TiO 2 photocatalyst It is X wt% Pt-TiO 2 , wherein X wt% Pt-TiO 2 is obtained by the following formula:
，X＝0.1~2.0。 , X = 0.1~2.0.
其中，本發明鉑金改質二氧化鈦光觸媒的光沉積法製備方法的實施例中，X＝5、10、15、20。In the embodiment of the method for preparing a platinum-modified titanium dioxide photocatalyst of the present invention, X=5, 10, 15, and 20.
本發明更進一步提供一種利用有機廢水產氫方法，其方法步驟包括：The invention further provides a method for producing hydrogen by using organic wastewater, the method steps comprising:
將如前所述的製備方法製得的光觸媒分散於含有機物之廢水中，使該光觸媒作為犧牲劑參與光催化反應，並產氫以降解污染物；Dissolving the photocatalyst prepared by the preparation method as described above in the wastewater containing organic matter, causing the photocatalyst to participate in the photocatalytic reaction as a sacrificial agent, and generating hydrogen to degrade the pollutant;
將前述溶液伴以攪拌地進行曝氣，以形成無氧環境。The aforementioned solution was aerated with agitation to form an oxygen-free environment.
其中，本發明利用有機廢水產氫方法的實施例中，該廢水中的有機物包括甲醇(Methanol)、乙醇(ethanol)、正丙醇(n-propanol)、異丙醇(i-propanol)、正丁醇(n-butanol)、叔丁醇（t-butanol）、乙二醇(ethylene glycol)、丙二醇(1,2-propanediol)、1,3-丙二醇(1,3-propanediol)以及丙三醇(glycerol)。Wherein the embodiment of the present invention utilizes an organic wastewater production method, the organic matter in the wastewater includes methanol (ethanol), ethanol, n-propanol, i-propanol, and positive Butyl alcohol (n-butanol), t-butanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, and glycerol (glycerol).
為利於對本發明的瞭解，以下結合附圖及實施例進行說明。To facilitate the understanding of the present invention, the following description is made in conjunction with the drawings and the embodiments.
本發明特徵與優點的一些實施例將在以下說明中詳細敘述。應理解的是本發明能夠在不同的態樣上具有各種的變化，然其皆不脫離本發明的範圍，且其中的說明及圖式在本質上係當作說明之用，而非用於限制本發明。Some embodiments of the features and advantages of the present invention are described in detail in the following description. It is to be understood that the invention is capable of various modifications in the various aspects of the invention this invention.
本發明實施例通過利用光沉積法與水熱法對二氧化鈦（TiO2 ）進行貴金屬鉑（Pt）與非金屬石墨烯（Graphene，於本發明中縮寫為GN）修飾改性，用以提高光催化產氫效率，以製得包括GN/ TiO2 光觸媒、Pt- TiO2 光觸媒的二元材料以及包括Pt-GN/ TiO2 光觸媒的三元材料。前述光觸媒經由使用UV-vis、XRD、FTIR、SEM與TEM等儀器對所製備材料進行特性分析後，依據不同操作參數，將該複合光觸媒加入到含有機物之廢水作為犧牲劑參與光催化反應，同時可產氫與降解污染物。In the embodiment of the present invention, titanium dioxide (TiO 2 ) is modified by noble metal platinum (Pt) and non-metal graphene (Graphene, abbreviated as GN in the present invention) by photodeposition and hydrothermal method to improve photocatalysis. The hydrogen production efficiency is to produce a binary material including a GN/TiO 2 photocatalyst, a Pt-TiO 2 photocatalyst, and a ternary material including a Pt-GN/TiO 2 photocatalyst. The photocatalyst is subjected to characteristic analysis of the prepared material by using instruments such as UV-vis, XRD, FTIR, SEM and TEM, and then the composite photocatalyst is added to the wastewater containing the organic matter as a sacrificing agent to participate in the photocatalytic reaction according to different operating parameters. It can produce hydrogen and degrade pollutants.
以下請配合參閱圖1至圖19及表一至表七，說明本發明產氫材料製備方法及其產物用於有機廢水產氫的方法。Hereinafter, please refer to FIG. 1 to FIG. 19 and Tables 1 to 7 to illustrate a method for preparing a hydrogen-producing material of the present invention and a method for producing hydrogen from an organic wastewater.
實施例一 ：製備氧化石墨烯（Graphite oxide，GO） Example 1 : Preparation of Graphene Oxide (GO)
本實施例是使用改進的Hummers法合成石墨氧化物（GO）。一般，在劇烈磁力攪拌下，將2.5g天然石墨和1.25g NaNO3 粉末與H2SO4（125mL）在低於5℃下混合。然後，將7.5g KMnO4緩慢加入到三頸圓底燒瓶中，並將溫度保持在35℃以下。將所得混合物在35℃下攪拌30分鐘。下一步，將混合物用150mL去離子水稀釋，並在低於95℃下保持攪拌。加入去離子水後，將燒瓶密封並在劇烈攪拌下保持在95℃30分鐘。然後，在5分鐘內滴加20％H2 O2 。將混合物過濾，並用去離子水和0.1M HCl溶液交替洗滌幾次。最後，將混合物在110℃下在真空烘箱中乾燥12小時，得到氧化石墨粉末。This example is the synthesis of graphite oxide (GO) using the modified Hummers process. Typically, 2.5 g of natural graphite and 1.25 g of NaNO 3 powder were mixed with H 2 SO 4 (125 mL) at less than 5 ° C under vigorous magnetic stirring. Then, 7.5 g of KMnO4 was slowly added to the three-necked round bottom flask, and the temperature was kept below 35 °C. The resulting mixture was stirred at 35 ° C for 30 minutes. Next, the mixture was diluted with 150 mL of deionized water and kept stirring below 95 °C. After the addition of deionized water, the flask was sealed and kept at 95 ° C for 30 minutes with vigorous stirring. Then, 20% H 2 O 2 was added dropwise over 5 minutes. The mixture was filtered and washed several times with deionized water and 0.1 M HCl solution. Finally, the mixture was dried in a vacuum oven at 110 ° C for 12 hours to obtain a graphite oxide powder.
實施例二 ：製備石墨烯改質二氧化鈦複合光觸媒（GN/ TiO2 ） Example 2 : Preparation of graphene modified titanium dioxide composite photocatalyst (GN/TiO 2 )
本實施例是使用水熱法合成製備石墨烯改質二氧化鈦光觸媒（GN/ TiO2 ）。將一定比例的實施例一製備的氧化石墨烯粉末分散在100mL去離子水中，攪拌30分鐘，並超聲處理1小時。然後，加入10mg TiO2 和20mL乙二醇，並將混合物超聲處理30分鐘以形成均勻分散體。之後，將懸浮液置於100mL聚四氟乙烯內襯的密封高壓釜中並在120℃下保持10小時。然後，將所獲得的溶液過濾並用去離子水洗滌數次。最後，在80℃下在真空烘箱中乾燥6小時後，獲得GN/ TiO2 粉末。In this embodiment, a graphene-modified titanium dioxide photocatalyst (GN/TiO 2 ) is synthesized by hydrothermal synthesis. A certain proportion of the graphene oxide powder prepared in Example 1 was dispersed in 100 mL of deionized water, stirred for 30 minutes, and sonicated for 1 hour. Then, 10 mg of TiO 2 and 20 mL of ethylene glycol were added, and the mixture was sonicated for 30 minutes to form a uniform dispersion. Thereafter, the suspension was placed in a 100 mL polytetrafluoroethylene-lined sealed autoclave and kept at 120 ° C for 10 hours. The resulting solution was then filtered and washed several times with deionized water. Finally, after drying in a vacuum oven at 80 ° C for 6 hours, a GN / TiO 2 powder was obtained.
於本實施例中，通過改變氧化石墨烯的量，以獲得具有不同石墨烯含量的樣品。該GN/ TiO2 光觸媒的不同石墨烯含量記錄為X wt% GN/ TiO2 ，其中X wt% GN/ TiO2 是由下式計算獲得：In the present embodiment, samples having different graphene contents were obtained by changing the amount of graphene oxide. The different graphene content of the GN/TiO 2 photocatalyst was recorded as X wt% GN/TiO 2 , where X wt% GN/TiO 2 was calculated by the following formula:
，X＝5、10、15、20。 , X = 5, 10, 15, 20
實施例三 ：製備鉑金與石墨烯改質二氧化鈦光觸媒（Pt-GN/ TiO2 ） Example 3 : Preparation of platinum and graphene modified titanium dioxide photocatalyst (Pt-GN/TiO 2 )
於本實施例中，是以H2 PtCl6 為無機前驅體，通過原位光沉積法在GN/ TiO2 表面負載Pt，以形成Pt-GN/ TiO2 光觸媒。其中，採用光沉積法，以保證Pt在製備過程中幾乎完全沉積。在本實施例的光沉積反應中，使用乙二醇作為還原劑。在典型的合成中，將一定比例的上述製備的GN/ TiO2 分散在20.0mL乙二醇溶液中，並在劇烈攪拌下形成均勻的懸浮液。在乙二醇與GN/ TiO2 混合之後，將溶液攪拌2小時，然後轉移到封裝在石英內管內的具有8W高壓汞蒸氣燈（Phillips，254nm最大波長）的1000mL圓柱形石英光反應器中。向上述溶液中加入預定量的H2 PtCl6 ‧6H2 O和600mL去離子水。將混合物在連續攪拌和氮氣鼓泡下照射12小時。隨後，將溶液冷卻至室溫。最後，將離心過濾所得粉末用去離子水洗滌，並在110℃條件下乾燥6小時至隔夜，在300℃溫度下進行煆燒得到不同Pt負載量的最終產物。將最終產物研磨過（200目）備用。In the present embodiment, H 2 PtCl 6 is used as an inorganic precursor, and Pt is supported on the surface of GN/TiO 2 by in-situ photodeposition to form a Pt-GN/TiO 2 photocatalyst. Among them, photodeposition is used to ensure that Pt is almost completely deposited during the preparation process. In the photodeposition reaction of this example, ethylene glycol was used as a reducing agent. In a typical synthesis, a proportion of the GN/TiO 2 prepared above was dispersed in 20.0 mL of ethylene glycol solution and a homogeneous suspension was formed with vigorous stirring. After the ethylene glycol was mixed with GN/TiO 2 , the solution was stirred for 2 hours and then transferred to a 1000 mL cylindrical quartz photoreactor with an 8 W high pressure mercury vapor lamp (Phillips, 254 nm maximum wavelength) enclosed in a quartz inner tube. . A predetermined amount of H 2 PtCl 6 ‧6H 2 O and 600 mL of deionized water were added to the above solution. The mixture was irradiated for 12 hours under continuous stirring and nitrogen bubbling. Subsequently, the solution was cooled to room temperature. Finally, the powder obtained by centrifugal filtration was washed with deionized water and dried at 110 ° C for 6 hours to overnight, and calcined at 300 ° C to obtain a final product of different Pt loading. The final product was ground (200 mesh) for use.
於本實施例中，是通過H2 PtCl6 ‧6H2 O溶液的濃度計算光觸媒中的Pt含量（如下式(1)，由光光觸媒中的A，例如Pt或石墨烯的重量百分比表示）。此外，光觸媒中的實際Pt含量使用具有微波消解的電感耦合等離子體（ICP）測定。沉積在光觸媒上的Pt的百分比記錄為X wt% Pt-GN/ TiO2 ，其中，X＝0.1、0.5、1.0、1.5和2.0。In the present embodiment, the Pt content in the photocatalyst is calculated by the concentration of the H 2 PtCl 6 ‧6H 2 O solution (the following formula (1), expressed by the weight percentage of A in the photocatalyst, such as Pt or graphene). In addition, the actual Pt content in the photocatalyst is determined using inductively coupled plasma (ICP) with microwave digestion. The percentage of Pt deposited on the photocatalyst was recorded as X wt% Pt-GN/TiO 2 , where X = 0.1, 0.5, 1.0, 1.5 and 2.0.
式（1） Formula 1)
如圖1，顯示本發明實施例用於製備GN/ TiO2 及Pt-GN/ TiO2 的光沉積法製備裝置10，其包括石英反應器11、UV光源12、循環水13、磁力攪拌器14及氮氣源15。1 shows a photodeposition preparation apparatus 10 for preparing GN/TiO 2 and Pt-GN/TiO 2 according to an embodiment of the present invention, which comprises a quartz reactor 11, a UV light source 12, a circulating water 13, and a magnetic stirrer 14. And a nitrogen source 15.
實施例四 ：製備鉑金改質二氧化鈦光觸媒（Pt- TiO2 ） Example 4 : Preparation of Platinum Modified Titanium Dioxide Photocatalyst (Pt-TiO 2 )
於本發明實施例中，該Pt- TiO2 光觸媒的製備方法步驟與實施例三的Pt-GN/ TiO2 相近，差別僅在採用不含石墨烯成分的二氧化鈦與H2 PtCl6 ‧6H2 O，通過光沉積法進行反應，故不再贅述。In the embodiment of the present invention, the preparation method of the Pt-TiO 2 photocatalyst is similar to the Pt-GN/TiO 2 of the third embodiment, and the difference is only in the use of the titanium dioxide containing no graphene component and H 2 PtCl 6 ‧6H 2 O The reaction is carried out by photodeposition, so it will not be described again.
實施例五 ：利用有機廢水產氫方法 Embodiment 5 : Method for producing hydrogen by using organic wastewater
如圖2，顯示於本發明實施例中，用於氫氣生產的光觸媒製氫裝置20，其是由石英環形反應器21組成，該光觸媒製氫裝置20具有置於其中心作為UV光源24的8W高壓汞蒸氣燈（Phillips，254nm最大波長）和置於其外部的兩個500W氙燈，波長為400nm至800 nm作為可見光源23，通過水置換法的氣體收集和在反應器底部的磁力攪拌器22，以在實驗過程中保持光光觸媒懸浮。總反應器體積為800mL。通常，在連續磁力攪拌（速度＝800轉/分鐘）下，將0.08g光光觸媒懸浮在含有80mL犧牲劑的800mL混合物溶液中。在照射之前，通過用氮氣（10mL / min-1 ）吹掃30分鐘以使混合物溶液脫氣，以在大氣壓下完全除去氧氣。定期收集氣體。通過裝配有熱導檢測器（GC-TCD，Clarus 580，MS-5A柱，氮氣載體）和填充有5分子篩的2μm不銹鋼柱的氣相色譜儀26分析氫含量。使用氮氣源25作為載氣，流速為30mL / min。GC-TCD的操作條件列於下表一。2, a photocatalyst hydrogen generator 20 for hydrogen production, which is composed of a quartz ring reactor 21 having a 8W placed at its center as a UV light source 24, in an embodiment of the present invention. High pressure mercury vapor lamp (Phillips, 254 nm maximum wavelength) and two 500 W xenon lamps placed outside, wavelength 400 nm to 800 nm as visible light source 23, gas collection by water displacement method and magnetic stirrer 22 at the bottom of the reactor To keep the photocatalyst suspended during the experiment. The total reactor volume was 800 mL. Typically, 0.08 g of photocatalyst was suspended in 800 mL of a mixture solution containing 80 mL of sacrificial under continuous magnetic stirring (speed = 800 rpm). Prior to the irradiation, the mixture solution was degassed by purging with nitrogen (10 mL / min -1 ) for 30 minutes to completely remove oxygen at atmospheric pressure. Collect gas regularly. The hydrogen content was analyzed by a gas chromatograph 26 equipped with a thermal conductivity detector (GC-TCD, Clarus 580, MS-5A column, nitrogen carrier) and a 2 μm stainless steel column packed with 5 molecular sieves. A nitrogen source 25 was used as the carrier gas at a flow rate of 30 mL / min. The operating conditions for GC-TCD are listed in Table 1 below.
下表二顯示本發明實施例在不同條件下，於室溫進行的光催化反應的氫氣產生效率及其與鉑和石墨烯負載含量、光觸媒濃度、犧牲劑濃度和類型和循環時間等數據。
以上說明了本發明製備氧化石墨烯（GO）、石墨烯改質二氧化鈦光觸媒（GN/ TiO2 ）、鉑改質二氧化鈦光觸媒（Pt- TiO2 ）以及鉑-石墨烯改質二氧化鈦光觸媒（Pt-GN/ TiO2 ）的製備方法，以下請配合參閱圖3至圖10，說明本發明實施例製得之光觸媒的特性分析結果。The above describes the preparation of graphene oxide (GO), graphene modified titanium dioxide photocatalyst (GN/TiO 2 ), platinum modified titanium dioxide photocatalyst (Pt-TiO 2 ), and platinum-graphene modified titanium dioxide photocatalyst (Pt-GN). preparation / TiO 2) method, with the following Please refer to FIGS. 3 to 10, have described the characteristics analysis results of the photocatalyst prepared in Example embodiments of the present invention.
於本發明實施例中，光觸媒特性分析是使用A UV光譜儀（UV-vis / DRS，Hitachi，U-3900）記錄UV-vis漫反射光譜，在200-800nm的範圍內記錄光譜，以分析光觸媒的光學性質，如圖3、圖4及下表三。In the embodiment of the present invention, the photocatalytic property analysis is to record the UV-vis diffuse reflection spectrum using an A UV spectrometer (UV-vis / DRS, Hitachi, U-3900), and record the spectrum in the range of 200-800 nm to analyze the photocatalyst. Optical properties, as shown in Figure 3, Figure 4 and Table 3.
如圖3所示，裸露的TiO2 顯示低於384nm的強和寬的吸收帶，並且相應地計算的Eg為3.23eV，這與報告幾乎一致。隨著Pt負載增加，Eg值從3.23eV順序地移動到2.92eV。換句話說，由於Pt顆粒負載，吸收邊移動到較長的波長。圖3顯示對於0.1,0.5,1.0,1.5和2.0wt%的Pt- TiO2 ，吸收帶邊緣分別從384nm偏移到425nm。吸收邊緣的移動可歸因於能帶隙內的額外Pt雜質能級，其導致純TiO2的帶隙能量的減少。As shown in Figure 3, the bare TiO 2 showed a strong and broad absorption band below 384 nm, and the corresponding calculated Eg was 3.23 eV, which is almost consistent with the report. As the Pt load increases, the Eg value sequentially moves from 3.23 eV to 2.92 eV. In other words, the absorption edge moves to a longer wavelength due to the Pt particle loading. Figure 3 shows that for 0.1, 0.5, 1.0, 1.5 and 2.0 wt% Pt-TiO 2 , the absorption band edges are shifted from 384 nm to 425 nm, respectively. The movement of the absorption edge can be attributed to an additional Pt impurity level within the band gap, which results in a reduction in the band gap energy of pure TiO2.
如圖4所示，GN/ TiO2 複合材料具有與裸TiO2 相似的吸收光譜，並且在吸收邊緣具有明顯的紅移。在可見光中的延長的吸收可歸因於石墨烯與TiO2 的組合。As shown in Figure 4, the GN/TiO 2 composite has an absorption spectrum similar to that of bare TiO 2 and has a significant red shift at the absorption edge. The extended absorption in visible light can be attributed to the combination of graphene and TiO 2 .
本發明實施例通過使用電感耦合等離子體（ICP）技術測定Pt- TiO2 的實際Pt負載量。將樣品溶解在酸溶液（HCl:HNO3 ＝3:1）中，然後將溶液微波處理15分鐘，並稀釋至儀器檢測範圍內的濃度。GN/ TiO2 的實際石墨烯含量使用Elementar分析儀（EA，vario MICRO cube）測定。Pt和石墨烯含量表示為Pt或石墨烯重量百分比，如下表四所示。根據ICP結果，所有樣品的Pt實際負載量略低於理論值，表明通過該方法引入Pt的效率較低。此外，可以得出結論，通過水熱法摻入石墨烯已經獲得了良好的效果。Embodiments of the present invention determine the actual Pt loading of Pt-TiO 2 by using an inductively coupled plasma (ICP) technique. The sample was dissolved in an acid solution (HCl: HNO3 = 3:1), and then the solution was microwaved for 15 minutes and diluted to a concentration within the detection range of the instrument. The actual graphene content of GN/TiO 2 was measured using an Elementar analyzer (EA, vario MICRO cube). The Pt and graphene contents are expressed as Pt or graphene weight percentages as shown in Table 4 below. According to the ICP results, the actual Pt loading of all samples was slightly lower than the theoretical value, indicating that the efficiency of introducing Pt by this method was low. In addition, it can be concluded that good results have been obtained by hydrothermal addition of graphene.
本發明實施例通過使用ASAP 2020裝置，在77K下的氮吸附-解吸等溫線測定合成的光觸媒，和使用Brunauer-Emmett-Teller（BET）以及Barrett-Joyner-Halenda（BJH）計算方法，進行N2 吸附－解吸測量，以獲得比表面積。In the examples of the present invention, the synthesized photocatalyst was measured by a nitrogen adsorption-desorption isotherm at 77 K by using an ASAP 2020 apparatus, and the calculation method was performed using Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) calculation methods. 2 adsorption-desorption measurements to obtain specific surface area.
與裸TiO2 相比，Pt- TiO2 複合材料的比表面積沒有顯著變化，如下表五所示。觀察到當Pt負載量從0.1增加到2.0wt%時，Pt- TiO2 的表面積從51.3微米降低到48.7平方米/克。這歸因於Pt顆粒在TiO2 上的聚集，並且一部分Pt顆粒已經***到TiO2 之間的空間中。The specific surface area of the Pt-TiO 2 composite did not change significantly compared to bare TiO 2 , as shown in Table 5 below. It was observed that when the Pt loading was increased from 0.1 to 2.0 wt%, the surface area of Pt-TiO 2 was reduced from 51.3 μm to 48.7 m 2 /g. This is attributed to the aggregation of Pt particles on TiO 2 and a portion of the Pt particles have been inserted into the space between the TiO 2 .
根據表面積的結果，石墨烯的添加對GN/ TiO2 的表面積有很大的影響。通過摻入5wt%的石墨烯與TiO2 ，比表面積從52.3g/m2 增加到89.6m2 /g。這是由於石墨烯的大的理論比表面積（900-1200m2 g-1 ）。在20wt%石墨烯負載量下，表面積達到最大值（192.6m2 g-1 ）。As a result of the surface area, the addition of graphene has a large influence on the surface area of GN/TiO 2 . By incorporating 5 wt% of graphene and TiO 2 , the specific surface area is increased from 52.3 g/m 2 to 89.6 m 2 /g. This is due to the large theoretical specific surface area of graphene (900-1200 m 2 g -1 ). At a loading of 20 wt% graphene, the surface area reached a maximum (192.6 m 2 g -1 ).
本發明實施例中，光觸媒的晶相通過X射線衍射儀（XRD，X'Pert PRO），在20-80°的2θ範圍內，使用CuKα輻射加速電壓40kV和電流30Ma進行測定，如圖5、圖6。In the embodiment of the present invention, the crystal phase of the photocatalyst is measured by an X-ray diffractometer (XRD, X'Pert PRO) in a range of 20-80° 2θ, using a CuKα radiation acceleration voltage of 40 kV and a current of 30 Ma, as shown in FIG. 5 . Figure 6.
Pt- TiO2 和GN/ TiO2 的XRD圖案類似於裸TiO2 。如圖5和6所示，在25.3°，37.9°和48.2°的2θ值處發現主峰，它們分別對應於（1 1 0）、（0 0 4）和（2 0 0）面為銳鈦礦TiO2 指數。同時，沒有出現2θ值為27.4°，36.2°和41.2°的金紅石相的特徵峰。因此，製備的Pt- TiO2 粉末是良好結晶的純銳鈦礦。在Pt- TiO2 粉末的XRD圖案中沒有檢測到Pt相，可能是因為TiO2 表面上的Pt負載量不足以形成不同的結晶。The XRD patterns of Pt-TiO 2 and GN/TiO 2 are similar to bare TiO 2 . As shown in Figures 5 and 6, the main peaks were found at 2θ values of 25.3°, 37.9° and 48.2°, which correspond to the (1 1 0), (0 0 4) and (200) faces, respectively. TiO 2 index. At the same time, there are no characteristic peaks of the rutile phase with 2θ values of 27.4°, 36.2° and 41.2°. Therefore, the prepared Pt-TiO 2 powder is a pure crystalline anatase which is well crystallized. No Pt phase was detected in the XRD pattern of the Pt-TiO 2 powder, probably because the Pt loading on the surface of the TiO 2 was insufficient to form a different crystal.
金紅石相的CB電位低於H2 /H2O的標準氧化還原電位。因此，在標準條件下它不能將純水光還原成氫。這是TiO2 的銳鈦礦相更有利於光催化氫生產的一個原因。The CB potential of the rutile phase is lower than the standard redox potential of H 2 /H 2 O. Therefore, it cannot reduce pure water to hydrogen under standard conditions. This is one reason why the anatase phase of TiO 2 is more favorable for photocatalytic hydrogen production.
本發明實施例通過記錄和分析合成的光觸媒的傅里葉變換紅外光譜（FTIR，NiCoLET-iS10）以確定光觸媒中的表面官能團；其掃描波長為4000至800cm-1 ，採用自支撐Br顆粒技術。Pt- TiO2 和GN/ TiO2 複合材料的比較FTIR光譜如圖7和圖8所示。In the present invention, the Fourier transform infrared spectroscopy (FTIR, NiCoLET-iS10) of the synthesized photocatalyst was recorded and analyzed to determine surface functional groups in the photocatalyst; the scanning wavelength was 4000 to 800 cm -1 , and the self-supporting Br particle technique was employed. Comparative FTIR spectra of Pt-TiO 2 and GN/TiO 2 composites are shown in Figures 7 and 8.
結果顯示Pt- TiO2 的所有光譜與TiO2 的光譜相似。也就是說，Pt顆粒在TiO2 上的沉積對錶面官能團絕對沒有影響，這與低Pt負載量和XRD結果一致。從圖7可以看出，Pt- TiO2 的所有光譜在3429cm-1 處表現出強的峰，這是由於O-H的伸縮振動。在1300cm-1附近出現的峰歸因於Ti-O-Ti。The results show that all spectra of Pt-TiO 2 are similar to those of TiO 2 . That is, the deposition of Pt particles on TiO 2 has absolutely no effect on the surface functional groups, which is consistent with low Pt loading and XRD results. As can be seen from Fig. 7, all the spectra of Pt-TiO 2 showed a strong peak at 3429 cm -1 due to the stretching vibration of OH. The peak appearing around 1300 cm-1 is attributed to Ti-O-Ti.
如圖8所示，氧化石墨烯（GO）顯示出含氧官能團的幾個特徵峰。在約3000-3500cm-1 處的寬峰是由於C-OH基團的O-H伸縮振動。1720cm-1 處的峰和1620cm-1 處的峰分別歸因於C=O和C=C的骨架振動。此外，在1233cm-1 處觀察到的峰可能是由於C-O-C拉伸模式，並且在1039cm-1 附近出現的峰可能來自Ti-O-C。與圖8中的GO的光譜相比，它揭示了當GO與TiO2 複合時，含氧官能團（O-H，C=O，C=C和C-O-C）這可以表明在醇熱過程中氧化石墨烯被還原。這些FTIR的結果幾乎與已知的GN/ TiO2 複合材料的結果相容。As shown in Fig. 8, graphene oxide (GO) shows several characteristic peaks of an oxygen-containing functional group. The broad peak at about 3000-3500 cm -1 is due to the OH stretching vibration of the C-OH group. Peak at 1720cm -1 and the peaks at 1620cm -1 due to the skeletal vibration of C = O and C = C's. Furthermore, the peak observed at 1233 cm -1 may be due to the COC stretching mode, and the peak appearing around 1039 cm -1 may be derived from Ti-OC. Compared with the spectrum of GO in Fig. 8, it reveals that when GO is combined with TiO 2 , oxygen-containing functional groups (OH, C=O, C=C and COC) can indicate that graphene oxide is oxidized during the alcohol heat process. reduction. The results of these FTIRs are almost compatible with the results of known GN/TiO 2 composites.
通過透射電子顯微鏡（TEM，JEOL，2000 FXII）（圖9）以及具有能量色散X射線（EDS）分析（Hitachi S-4800）的場致發射掃描電子顯微鏡（SEM）（圖10）測量光觸媒的形態。Photocatalyst morphology was measured by transmission electron microscopy (TEM, JEOL, 2000 FXII) (Fig. 9) and field emission scanning electron microscope (SEM) with energy dispersive X-ray (EDS) analysis (Hitachi S-4800) (Fig. 10) .
圖9顯示了光觸媒的TEM圖像，從中可以容易地區分出TiO2 和Pt顆粒。在圖9（a）和（b）中可以看出，Pt顆粒是納米級的，並且觀察到Pt顆粒的聚集。GN/ TiO2 複合材料中的大多數顆粒表現出在20和50nm之間的範圍內的直徑。Figure 9 shows a TEM image of a photocatalyst from which TiO 2 and Pt particles can be easily distinguished. As can be seen in Figures 9(a) and (b), the Pt particles are nanoscale and aggregation of Pt particles is observed. Most of the particles in the GN/TiO 2 composite exhibit a diameter in the range between 20 and 50 nm.
此外，Pt顆粒通過如圖10的SEM背散射電子圖像和如下表六的EDS分析證實，Pt和C含量略低於通過ICP和Elementar分析儀的組分分析。這可能是由於當樣品在ICP和元素分析器分析的預處理中時的質量損失。從圖中可以看出石墨烯的聚集。石墨烯的不可逆附聚是不可避免的，因為石墨烯片之間的強烈的范德華力。Further, the Pt particles were confirmed by the SEM backscattered electron image as shown in FIG. 10 and the EDS analysis of Table 6 below, and the Pt and C contents were slightly lower than the composition analysis by the ICP and Elementar analyzer. This may be due to mass loss when the sample is in the pretreatment of the ICP and elemental analyzer analysis. The aggregation of graphene can be seen from the figure. The irreversible agglomeration of graphene is inevitable because of the strong van der Waals forces between the graphene sheets.
以下請配合參閱圖11至圖19，說明本發明實施例製得之光觸媒用於利用有機廢水產氫的功效。Hereinafter, please refer to FIG. 11 to FIG. 19 to illustrate the effect of the photocatalyst prepared by the embodiment of the present invention for producing hydrogen by using organic wastewater.
如圖11和圖12所示，顯示本發明實施例中，具有不同Pt負載量的Pt- TiO2 對光催化氫生產效率的影響。隨著Pt負載量從0.1到1.0wt%的增加，光催化氫產生的效率從1.91逐漸提高到4.71mmolh-1 g-1 。當Pt含量高於1.0wt%時，進一步增加Pt負載量會急劇降低氫氣產生速率。當Pt含量為1.0wt%時，最大氫產生速率為約4.71mmolh-1 g-1 。目前對於光催化氫的製備，最佳的Pt負載量為0.1-2.0wt%，通常低於1.5wt%，這與本發明實施例的結果一致。As shown in Fig. 11 and Fig. 12, the effect of Pt-TiO 2 having different Pt loadings on photocatalytic hydrogen production efficiency in the examples of the present invention is shown. As the Pt loading increased from 0.1 to 1.0 wt%, the efficiency of photocatalytic hydrogen production gradually increased from 1.91 to 4.71 mmolh -1 g -1 . When the Pt content is higher than 1.0 wt%, further increase in the Pt loading amount drastically reduces the hydrogen generation rate. When the Pt content is 1.0 wt%, the maximum hydrogen production rate is about 4.71 mmolh -1 g -1 . At present, for the preparation of photocatalytic hydrogen, the optimum Pt loading is from 0.1 to 2.0% by weight, usually less than 1.5% by weight, which is consistent with the results of the examples of the present invention.
當Pt含量在0.1和1.0wt%之間時，增加的光催化氫生成速率是由於有效的光致電子從TiO2 的CB轉移到TiO2 和Pt的接觸表面處的Pt顆粒，這降低了e- /h+重組和提高光催化氫生成速率。然而，當Pt含量低於0.1wt%時，較低的Pt分散會散射光照射並抑制光吸收。此外，它還導致非常弱的電子俘獲能力和活性位點的急劇減少，因此導致低的氫氣生產效率。另一方面，當Pt含量高於1.0wt%時，由於Pt顆粒在TiO2 表面上的生長和聚集，TiO2 表面上的Pt分散隨著負載含量的增加而降低。又，過量的Pt顆粒繼而充當光生電子/空穴對的複合中心，導致氫氣產生的效率低。When the Pt content is between 0.1 and 1.0wt%, increasing photocatalytic hydrogen generation rate due to efficient photoinduced electron transfer from TiO CB 2 to Pt particles at the contact surface of the TiO 2 and Pt, which reduces e - /h+ recombines and increases the rate of photocatalytic hydrogen generation. However, when the Pt content is less than 0.1% by weight, the lower Pt dispersion scatters light irradiation and suppresses light absorption. In addition, it also results in very weak electron capture capability and a sharp decrease in active sites, thus resulting in low hydrogen production efficiency. On the other hand, when the Pt content is higher than 1.0wt%, since the Pt particle growth and aggregation on the surface of the TiO 2, TiO 2 on the surface of Pt dispersion content increases as the load decreases. Again, excess Pt particles in turn act as recombination centers for photogenerated electron/hole pairs, resulting in low efficiency of hydrogen production.
另，Pt和TiO2 界面之間的肖特基勢壘也影響光催化氫生產活性。TiO2 上的Pt顆粒產生肖特基勢壘，促進光生電子俘獲。具有適當功函數的金屬Pt增加了金屬和TiO2 界面之間的肖特基勢壘效應，這可以有效地限制電子/空穴對的複合。當Pt含量低於1.0wt%時，Pt和TiO2 界面處的肖特基勢壘數量隨著Pt負載的增加而增加，導致更多的電子捕獲和光催化氫生產效率的提高。當Pt負載量高於1.0wt%時，用於TiO2 表面上的光反應的活性位點被過量的Pt覆蓋並部分阻塞，因此導致低效率的激發。考慮到這些因素，合適的Pt負載量在光催化氫生產中起重要作用。In addition, the Schottky barrier between the Pt and TiO 2 interfaces also affects photocatalytic hydrogen production activity. The Pt particles on TiO 2 create a Schottky barrier that promotes photogenerated electron capture. The metal Pt with an appropriate work function increases the Schottky barrier effect between the metal and TiO 2 interfaces, which can effectively limit the recombination of electron/hole pairs. When the Pt content is less than 1.0% by weight, the number of Schottky barriers at the interface between Pt and TiO 2 increases as the Pt load increases, resulting in more electron capture and photocatalytic hydrogen production efficiency. When the Pt loading is higher than 1.0 wt%, the active site for photoreaction on the surface of TiO 2 is covered by excess Pt and partially blocked, thus resulting in inefficient excitation. In view of these factors, a suitable Pt loading plays an important role in photocatalytic hydrogen production.
提高光催化效率的有效方法是增加光觸媒的表面積。這可以通過用石墨烯改性TiO2 來實現，其以其高的理論比表面積是眾所周知的。此外，與其他半導體偶聯的石墨烯對污染物降解的光催化活性，如孔雀綠草酸鹽和阿莫西林表現出積極的影響。圖13和圖14顯示了GN/ TiO2 對氫氣產生的光催化活性的結果。從圖中可以看出，將石墨烯引入TiO2 可以導致光催化氫生產效率的顯著改善。結果，通過10wt%的GN/ TiO2 複合材料達到最佳的光催化效率。添加小含量的石墨烯，小於10wt%，也可以顯著提高TiO2 的光催化活性。然而，當石墨烯添加比例大於10wt%時，效率隨著GN/ TiO2 光觸媒的石墨烯含量的增加而下降。主要原因是過量加入黑色石墨烯導致光觸媒表面活性位點的屏蔽，增加了入射光的散射功能，降低了光催化反應的光強。所有這些使得在反應過程中發生屏蔽效應，這將降低光催化活性的效率。An effective way to increase photocatalytic efficiency is to increase the surface area of the photocatalyst. This can be achieved by modifying TiO 2 with graphene, which is well known for its high theoretical specific surface area. In addition, graphene coupled with other semiconductors exhibits a positive effect on the photocatalytic activity of contaminant degradation such as peacock oxalate and amoxicillin. Figures 13 and 14 show the results of the photocatalytic activity of GN/TiO 2 for hydrogen production. As can be seen from the figure, the introduction of graphene into TiO 2 can result in a significant improvement in photocatalytic hydrogen production efficiency. As a result, optimum photocatalytic efficiency was achieved by a 10 wt% GN/TiO 2 composite. The addition of a small amount of graphene, less than 10% by weight, can also significantly increase the photocatalytic activity of TiO 2 . However, when the graphene addition ratio is more than 10% by weight, the efficiency decreases as the graphene content of the GN/TiO 2 photocatalyst increases. The main reason is that the excessive addition of black graphene leads to the shielding of the active site of the photocatalyst, increases the scattering function of the incident light, and reduces the light intensity of the photocatalytic reaction. All of this causes a shielding effect to occur during the reaction, which will reduce the efficiency of photocatalytic activity.
從一元醇超過0.5PGT10的氫產生的結果如圖15和圖16所示。由於溶劑性質可以顯著影響電子轉移動力學，這些一元醇超過0.5PGT10（0.5wt.% Pt-10 wt.% GN/ TiO2 ）的氫氣產生速率與它們的極性相關，如下定義，氫生產速率對一元醇的極性的結果示於圖17和下表七中。The results from hydrogen production of monohydric alcohol exceeding 0.5 PGT10 are shown in Figures 15 and 16. Since the nature of the solvent can significantly affect the electron transfer kinetics, the hydrogen production rates of these monohydric alcohols exceeding 0.5 PGT10 (0.5 wt.% Pt-10 wt.% GN/TiO 2 ) are related to their polarity, as defined below, the hydrogen production rate is The results of the polarities of the monohydric alcohol are shown in Figure 17 and in Table VII below.
，其中，εs是相對溶劑介電常數，Y是極性。 Where εs is the relative solvent dielectric constant and Y is the polarity.
從圖18中可以看出，氫氣產生速率和一元醇的極性之間存在明顯的線性關係。圖19顯示了通過0.5PTG10的氫氣產生速率，其速率遵循以下順序：甘油＞乙二醇＞甲醇＞1,3-丙二醇＞1,2-丙二醇＞乙醇＞正丙醇。簡單來說，這個順序可以寫成三元＞二元＞一元醇。考慮在乙醇和1,2-乙二醇（相同數量的碳）中收集的數據集以及在正丙醇，1,2-丙二醇，1,3-丙二醇和甘油（相同數量的碳）中收集的數據集，顯示氫氣產生速率跟踪醇上的羥基數。氫生成速率隨著醇上的OH基團的數目而增加的原因可能是複雜的，因為OH基團的數目影響光觸媒上的醇極性，醇吸附強度和結合模式以及醇的氧化電位。As can be seen from Figure 18, there is a clear linear relationship between the rate of hydrogen production and the polarity of the monohydric alcohol. Figure 19 shows the rate of hydrogen production by 0.5 PTG10 at a rate that follows the following sequence: glycerol > ethylene glycol > methanol > 1,3-propanediol > 1,2-propanediol > ethanol > n-propanol. Simply put, this order can be written as ternary > binary > monohydric alcohol. Consider data sets collected in ethanol and 1,2-ethanediol (same amount of carbon) and in n-propanol, 1,2-propanediol, 1,3-propanediol and glycerol (same amount of carbon) The data set shows the rate of hydrogen production tracking the number of hydroxyl groups on the alcohol. The reason why the rate of hydrogen generation increases with the number of OH groups on the alcohol may be complicated because the number of OH groups affects the polarity of the alcohol on the photocatalyst, the strength of the alcohol adsorption and the mode of binding, and the oxidation potential of the alcohol.
綜上，本發明實施例通過改性Hummers法，水熱法和光沉積法成功合成了Pt- TiO2 ，GN/ TiO2 ，Pt- TiO2 ，Pt-GN/ TiO2 。通過UV-vis/DRS，組分分析，XRD，FTIR，SEM-EDS和TEM分析對合成的光觸媒進行表徵。UV-vis/DRS結果表明，當Pt負載增加時，Pt- TiO2 的Eg值從3.23降低到2.92eV，隨著石墨烯負載量增加，GN/ TiO2 的Eg值從2.94降低到2.26eVKubelka-Munk函數理論。GN/ TiO2 的FTIR結果表明，在光觸媒中存在一些含氧官能團。TEM分析證實在TiO2 的表面上存在Pt，並觀察到Pt顆粒的聚集。組分的結果分析顯示，所有樣品的Pt實際加載含量略低於理論值，表明通過該方法摻入Pt的效率較低。然而，通過水熱法摻入石墨烯已經獲得了良好的效果。In summary, the present invention successfully synthesized Pt-TiO 2 , GN / TiO 2 , Pt- TiO 2 , Pt-GN / TiO 2 by modified Hummers method, hydrothermal method and photodeposition method. The synthesized photocatalyst was characterized by UV-vis/DRS, component analysis, XRD, FTIR, SEM-EDS and TEM analysis. UV-vis/DRS results show that when the Pt loading increases, the Eg value of Pt-TiO 2 decreases from 3.23 to 2.92 eV. As the graphene loading increases, the Eg value of GN/TiO 2 decreases from 2.94 to 2.26 eV Kubelka- Munk function theory. The FTIR results of GN/TiO 2 indicate that some oxygen-containing functional groups are present in the photocatalyst. TEM analysis confirmed the presence of Pt on the surface of TiO 2 and observed the aggregation of Pt particles. Analysis of the results of the components showed that the actual loading of Pt of all samples was slightly lower than the theoretical value, indicating that the efficiency of incorporation of Pt by this method was low. However, good results have been obtained by hydrothermally incorporating graphene.
進一步地，將前述光觸媒產品用於利用有機廢水產氫的方法時，Further, when the photocatalyst product is used in a method of producing hydrogen using organic wastewater,
當Pt含量為1.0wt%時，最大氫產生速率為約4.71mmolh-1 g--1 。高於和低於1.0wt%的Pt負載量都導致低的氫氣產生效率。石墨烯的情況類似於Pt。石墨烯的最佳比例為10wt%。最高的氫氣產生速率為6.58mmolh-1 g-1 × 1.5 wt% Pt-5 wt% GN/ TiO2 （1.5PTG5），其大約是Pt- TiO2 和GN/ TiO2 二元復合材料。使用低成本石墨烯可以減少貴金屬Pt在光催化氫生產中的使用。提出Pt-GN/ TiO2 改善光催化活性的機理。發現0.1gL-1 是用於最佳氫生產的最佳光觸媒濃度。過量的光觸媒可能導致反應溶液的不透明性，並且光強度降低。When the Pt content is 1.0% by weight, the maximum hydrogen production rate is about 4.71 mmolh -1 g - -1 . Higher than and below 1.0 wt% Pt loading results in low hydrogen production efficiency. The case of graphene is similar to Pt. The optimum ratio of graphene is 10% by weight. The highest hydrogen production rate was 6.58 mmolh -1 g -1 × 1.5 wt% Pt-5 wt% GN/TiO 2 (1.5PTG5), which is approximately a Pt-TiO 2 and GN/TiO 2 binary composite. The use of low cost graphene can reduce the use of precious metal Pt in photocatalytic hydrogen production. The mechanism of Pt-GN/TiO 2 improving photocatalytic activity was proposed. 0.1 g L -1 was found to be the optimum photocatalyst concentration for optimal hydrogen production. Excessive photocatalyst may result in opacity of the reaction solution and a decrease in light intensity.
再者，不同的犧牲劑（甲醇，乙醇，正丙醇，異丙醇，正丁醇，乙二醇，1,2-丙二醇，1,3-丙二醇和甘油），在氫氣產生速率和一元醇的極性之間存在明顯的線性關係，在較高的初始甲醇濃度下，氫氣產生速率應該變得恆定，這使得反應與零級動力學匹配。在較低的初始濃度下，氫氣產生速率與初始甲醇濃度成比例。Furthermore, different sacrificial agents (methanol, ethanol, n-propanol, isopropanol, n-butanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol and glycerol), in hydrogen production rate and monohydric alcohol There is a clear linear relationship between the polarities, and at higher initial methanol concentrations, the rate of hydrogen production should become constant, which matches the reaction to zero-order kinetics. At lower initial concentrations, the rate of hydrogen production is proportional to the initial methanol concentration.
又，在相同實驗條件下重複使用光觸媒之後，氫氣產生速率僅略微降低3個循環，這表明合成的光觸媒的穩定性。Also, after repeated use of the photocatalyst under the same experimental conditions, the hydrogen generation rate was only slightly reduced by 3 cycles, indicating the stability of the synthesized photocatalyst.
10‧‧‧光沉積法製備裝置 10‧‧‧Photodeposition preparation device
11‧‧‧石英反應器 11‧‧‧Quartz reactor
12‧‧‧UV光源 12‧‧‧UV light source
13‧‧‧循環水 13‧‧‧Circulating water
14‧‧‧磁力攪拌器 14‧‧‧Magnetic mixer
15‧‧‧氮氣源 15‧‧‧Nitrogen source
20‧‧‧光觸媒製氫裝置 20‧‧‧Photocatalyst hydrogen production unit
21‧‧‧石英環形反應器 21‧‧‧Quartz ring reactor
22‧‧‧磁力攪拌器 22‧‧‧Magnetic stirrer
23‧‧‧UV光源 23‧‧‧UV light source
24‧‧‧可見光源 24‧‧‧ Visible light source
25‧‧‧氮氣源 25‧‧‧Nitrogen source
26‧‧‧氣相層析儀 26‧‧‧ gas chromatograph
圖1係本發明光沉積法製備裝置的架構示意圖。 圖2係本發明光觸媒製氫裝置的架構示意圖。 圖3係本發明Pt- TiO2 之UV-vis圖譜。 圖4係本發明GN/ TiO2 之UV-vis圖譜。 圖5係本發明Pt- TiO2 之XRD繞射圖。 圖6係本發明GN/ TiO2 之XRD繞射圖。 圖7係本發明Pt- TiO2 之傅立葉紅外線光譜圖。 圖8係本發明GN/ TiO2 之傅立葉紅外線光譜圖。 圖9係本發明0.5 wt%Pt- TiO2 （(a)小圖）、1.0 wt%Pt- TiO2 （(b)小圖）之穿透式電子顯微鏡圖（TEM）。 圖10係本發明0.5 wt%Pt- TiO2 （(a)小圖）及1.0 wt%Pt- TiO2 之掃描電子顯微鏡圖（SEM）。 圖11係本發明不同Pt含量的Pt- TiO2 與氫氣產量、反應時間的關係圖。 圖12係本發明不同Pt含量光催化產氫速率比較結果。 圖13係本發明不同石墨烯含量的GN/ TiO2 與氫氣產量、反應時間的關係圖。 圖14係本發明不同石墨烯含量光催化產氫進率比較結果。 圖15係本發明以不同醇類與三元材料0.5 wt.% Pt-10 wt.% GN/ TiO2 光觸媒（0.5PTG10）進行反應的氫氣產量、反應時間的關係圖。 圖16係本發明0.5 wt.% Pt-10 wt.% GN/ TiO2 （0.5PTG10）用於各種醇廢水光催化產氫速率比較結果。 圖17係本發明產氫速率與不同醇類極性的關係示意圖。 圖18係本發明以甘油、不同醇類與三元材料0.5 wt.% Pt-10 wt.% GN/ TiO2 光觸媒（0.5PTG10）進行反應的氫氣產量、反應時間的關係圖。 圖19係本發明0.5 wt.% Pt-10 wt.% GN/ TiO2 （0.5PTG10）用於各種醇廢水光催化產氫速率比較結果。1 is a schematic view showing the structure of a photodeposition preparation apparatus of the present invention. 2 is a schematic view showing the structure of a photocatalyst hydrogen producing apparatus of the present invention. Figure 3 is a UV-vis spectrum of Pt-TiO 2 of the present invention. Figure 4 is a UV-vis spectrum of the GN/TiO 2 of the present invention. Figure 5 is an XRD diffraction pattern of Pt-TiO 2 of the present invention. Figure 6 is an XRD diffraction pattern of GN/TiO 2 of the present invention. Figure 7 is a Fourier infrared spectrum of Pt-TiO 2 of the present invention. Figure 8 is a Fourier infrared spectrum of GN/TiO 2 of the present invention. Figure 9 is a transmission electron micrograph (TEM) of 0.5 wt% Pt-TiO 2 ((a) panel), 1.0 wt% Pt-TiO 2 ((b) panel) of the present invention. Figure 10 is a scanning electron micrograph (SEM) of 0.5 wt% Pt-TiO 2 ((a) panel) and 1.0 wt% Pt-TiO 2 of the present invention. Figure 11 is a graph showing the relationship between Pt-TiO 2 with different Pt contents and hydrogen production and reaction time in the present invention. Fig. 12 is a comparison result of photocatalytic hydrogen production rates of different Pt contents of the present invention. Figure 13 is a graph showing the relationship between GN/TiO 2 with different graphene contents and hydrogen production and reaction time in the present invention. Fig. 14 is a comparison result of photocatalytic hydrogen production rate of different graphene contents in the present invention. Figure 15 is a graph showing the relationship between hydrogen production and reaction time for the reaction of different alcohols with a ternary material of 0.5 wt.% Pt-10 wt.% GN/TiO 2 photocatalyst (0.5PTG10). Figure 16 is a comparison of the photocatalytic hydrogen production rate of 0.5 wt.% Pt-10 wt.% GN/TiO 2 (0.5PTG10) for various alcohol wastewaters. Figure 17 is a graphical representation of the relationship between the hydrogen production rate of the present invention and the polarity of different alcohols. Figure 18 is a graph showing the relationship between hydrogen production and reaction time in the reaction of glycerin, different alcohols and ternary material 0.5 wt.% Pt-10 wt.% GN/TiO 2 photocatalyst (0.5PTG10). Figure 19 is a comparison of the photocatalytic hydrogen production rate of 0.5 wt.% Pt-10 wt.% GN/TiO 2 (0.5PTG10) for various alcohol wastewaters.
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| CN111560665A (en) * | 2020-04-24 | 2020-08-21 | 中国科学院化学研究所 | Pt-loaded B and N co-doped In2O3/TiO2Nano fiber and preparation method and application thereof |
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| CN111560665A (en) * | 2020-04-24 | 2020-08-21 | 中国科学院化学研究所 | Pt-loaded B and N co-doped In2O3/TiO2Nano fiber and preparation method and application thereof |
| CN111560665B (en) * | 2020-04-24 | 2021-12-14 | 中国科学院化学研究所 | Pt-loaded B and N co-doped In2O3/TiO2Nano fiber and preparation method and application thereof |
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