CN113135553B - 一种氮化钨包覆氮化钒粉体及其制备方法和应用 - Google Patents

一种氮化钨包覆氮化钒粉体及其制备方法和应用 Download PDF

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CN113135553B
CN113135553B CN202110433834.1A CN202110433834A CN113135553B CN 113135553 B CN113135553 B CN 113135553B CN 202110433834 A CN202110433834 A CN 202110433834A CN 113135553 B CN113135553 B CN 113135553B
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黄剑锋
李帅楠
冯亮亮
曹丽云
何丹阳
冯李
肖婷
张晓�
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Shaanxi University of Science and Technology
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Abstract

本发明公开了一种氮化钨包覆氮化钒粉体的制备方法,包括步骤一:按照质量比为(60~80):(10~20):(24~40)称取二甲基咪唑、氯化钒和二水合钨酸钠;步骤二:将上述粉料干混并研磨,装入瓷舟中,将瓷舟置于管式炉中,并在管两端各放两个炉塞;步骤三:排尽管式炉内空气,在惰性气氛下,以5~10℃/min升温加热,在300~400℃保温120~180min,继续升温在600~800℃保温120~180min;步骤四:保温结束后,冷却到室温,研磨黑色样品,得到目标产物VN@WN;本发明提供了一种成本低廉、含量丰富以及性能优异的电催化剂,为非贵金属电催化剂的开拓提供了新的思路,该方法操作简单,安全高效,产物结晶性好,纯度高,作为电解水产氢电极材料时电化学性能好。

Description

一种氮化钨包覆氮化钒粉体及其制备方法和应用
技术领域
本发明属于催化剂技术领域,具体涉及一种氮化钨包覆氮化钒粉体及其制备方法和应用。
背景技术
氢能因为其高能量密度和环境友好性而被认为是一种很有前途的替代传统化石燃料的绿色能源。在各种制氢技术中,电催化分解水是一种有效且有潜力的制氢技术,因为它对环境的低污染且受外部环境影响因素小。但最关键的是,这种绿色可持续发展的技术在很大程度上受到实际大规模应用中巨大能耗的限制,因为在电催化水裂解过程中主要取决于两个半反应,即产氢反应(HER)和产氧反应(OER)。这两个半反应都必须克服一定的反应势垒,并受到缓慢反应动力学的限制[Xing W,Miao X,Meng F,et al.Crystalstructure of and displacive phase transition in tungsten nitride WN[J].Journal of Alloys and Compounds,2017,722:517-524.]。那么开发高效稳定的电催化剂来弥补这些不足是非常需要的。贵金属铂基和钌/铱基催化剂对产氢和产氧的催化活性普遍优于其它催化剂,但其成本高、元素丰度低、稳定性差、功能单一等限制了其商业化和大规模应用,为了使电解水制取氢气得到大规模实际应用,通过设计经济高效、性能稳定的电催化剂迫在眉睫。
氮化物具有与Pt相似的d电子构型,是一种很有前途的电催化剂[Yang H,Ning P,Cao H,et al.Selectively Anchored Vanadate Host for Self-Boosting CatalyticSynthesis of Ultra-Fine Vanadium Nitride/Nitrogen-Doped Hierarchical CarbonHybrids as Superior Electrode Materials[J].Electrochimica Acta,332:135387]。但由于单相的氮化物合成温度较高,容易发生聚集,较小的比表面积抑制了产氢效率。值得注意的是,设计氮化物的复合材料是一种有效的方法,它可以重新分配电子密度来改变电子结构,从而调节反应物的吸附/脱附能,反应过程中的中间体和产物增强了催化活性。
发明内容
针对上述现有技术存在的不足,本发明的目的在于提供一种氮化钨包覆氮化钒粉体及其制备方法和应用,该方法操作简单、成本低廉,所得产物电催化性能优异。
为了实现上述目的,本发明采用以下技术方案予以实现:
一种氮化钨包覆氮化钒粉体的制备方法,包括以下步骤:
步骤一:按照质量比为(60~80):(10~20):(24~40)称取二甲基咪唑、氯化钒和二水合钨酸钠;
步骤二:将上述粉料干混并研磨,装入瓷舟中,将瓷舟置于管式炉中,并在管两端各放两个炉塞;
步骤三:排尽管式炉内空气,在惰性气氛下,以5~10℃/min升温加热,在300~400℃保温120~180min,继续升温在600~800℃保温120~180min;
步骤四:保温结束后,冷却到室温,研磨黑色样品,得到目标产物VN@WN。
本发明还具有以下技术特征:
优选的,所述的步骤二中原料混合后在玛瑙研钵中研磨30min。
优选的,所述步骤二中管式炉两端的两个炉塞间隔5cm放置。
优选的,所述的步骤三中排尽管式炉内空气的方法为向管内通入惰性气体,继而进行4~6次抽气补气以排尽管内空气,最后一次补气后不再抽气。
优选的,所述的惰性气体为氩气,气流速率为20~40sccm。
本发明还保护一种如上所述的氮化钨包覆氮化钒粉体的制备方法制备的氮化钨包覆氮化钒粉体及其应用。
本发明与现有技术相比,具有如下技术效果:
本发明提供了一种成本低廉、含量丰富以及性能优异的电催化剂,为非贵金属电催化剂的开拓提供了新的思路,该方法操作简单,安全高效;
本发明制备的VN@WN是由氮化钨包覆氮化钒形成的纳米颗粒,这种结构促进了两相的协同效应,保护了氮化钒材料,增加了材料的稳定性,同时材料氮含量的提高有益于增加材料的活性位点,继而能大大发挥产氢效率;
本发明制备的产物结晶性好,纯度高,形貌分散性比较好,作为电解水产氢电极材料时能够表现出令人满意的电化学性能,并且在10mA/cm2的电流密度下,其过电势约为191mV。
附图说明
图1是实施例2所制备的纳米VN@WN的XRD图谱
图2是实施例3所制备的纳米VN@WN的TEM图
图3是实施例4所制备的纳米VN@WN的产氢性能图
具体实施方式
以下结合实施例对本发明的具体内容做进一步详细解释说明。
实施例1:
1)按照质量比为60:10:24称取二甲基咪唑、氯化钒和二水合钨酸钠;
2)将上述粉料干混并在玛瑙研钵中研磨30min,装入瓷舟中,将瓷舟置于管式气氛炉中,并在管两端各放两个炉塞,间隔5cm;
3)向管内通入氩气,继而进行4次抽气补气,排尽管内空气,最后一次补气后不再抽气,以20sccm气流通入气氛,以5℃/min升温加热,在300℃保温120min,继续升温在600℃保温120min;
4)保温结束后,冷却到室温,研磨黑色样品,得到目标产物VN@WN。
实施例2:
1)按照质量比为70:15:32称取二甲基咪唑、氯化钒和二水合钨酸钠;
2)将上述粉料干混并在玛瑙研钵中研磨30min,装入瓷舟中,将瓷舟置于管式气氛炉中,并在管两端各放两个炉塞,间隔5cm;
3)向管内通入氩气,继而进行5次抽气补气,排尽管内空气,最后一次补气后不再抽气,以30sccm气流通入气氛,以10℃/min升温加热,在400℃保温180min,继续升温在700℃保温180min;
4)保温结束后,冷却到室温,研磨黑色样品,得到目标产物VN@WN。
实施例3:
1)按照质量比为80:20:40称取二甲基咪唑、氯化钒和二水合钨酸钠;
2)将上述粉料干混并在玛瑙研钵中研磨30min,装入瓷舟中,将瓷舟置于管式气氛炉中,并在管两端各放两个炉塞,间隔5cm;
3)向管内通入氩气,继而进行6次抽气补气,排尽管内空气,最后一次补气后不再抽气,以40sccm气流通入气氛,以5℃/min升温加热,在300℃保温120min,继续升温在800℃保温120min;
4)保温结束后,冷却到室温,研磨黑色样品,得到目标产物VN@WN。
实施例4:
1)按照质量比为70:20:40称取二甲基咪唑、氯化钒和二水合钨酸钠;
2)将上述粉料干混并在玛瑙研钵中研磨30min,装入瓷舟中,将瓷舟置于管式气氛炉中,并在管两端各放两个炉塞,间隔5cm;
3)向管内通入氩气,继而进行4次抽气补气,排尽管内空气,最后一次补气后不再抽气,以30sccm气流通入气氛,以10℃/min升温加热,在400℃保温180min,继续升温在700℃保温180min;
4)保温结束后,冷却到室温,研磨黑色样品,得到目标产物VN@WN。
实施例5:
1)按照质量比为80:10:24称取二甲基咪唑、氯化钒和二水合钨酸钠;
2)将上述粉料干混并在玛瑙研钵中研磨30min,装入瓷舟中,将瓷舟置于管式气氛炉中,并在管两端各放两个炉塞,间隔5cm;
3)向管内通入氩气,继而进行5次抽气补气,排尽管内空气,最后一次补气后不再抽气,以30sccm气流通入气氛,以8℃/min升温加热,在350℃保温160min,继续升温在700℃保温150min;
4)保温结束后,冷却到室温,研磨黑色样品,得到目标产物VN@WN。
图1是实施例2所制备的纳米VN@WN的XRD图谱,从图中可以看出样品衍射峰与标准卡片匹配良好,衍射峰非常尖锐,且无其他杂峰出现,说明该实施例得到的VN@WN结晶性好,纯度高;
图2是实施例3所制备的纳米VN@WN的TEM图,从图中可以看出VN@WN为氮化钨包覆氮化钒的结构,且0.24nm的晶格条纹对应VN的(111)晶面,0.19nm的晶格条纹对应WN的(101)晶面;
图3是实施例4所制备的纳米VN@WN的产氢性能图,表示pH 14测试条件下,当电流密度为10mA/cm2,扫描速率为3mV/s时,该样品过电势为191mV,说明具有优异的产氢性能。

Claims (7)

1.一种氮化钨包覆氮化钒粉体的制备方法,其特征在于,包括以下步骤:
步骤一:按照质量比为(60~80):(10~20):(24~40)称取二甲基咪唑、氯化钒和二水合钨酸钠;
步骤二:将上述粉料干混并研磨,装入瓷舟中,将瓷舟置于管式炉中,并在管两端各放两个炉塞;
步骤三:排尽管式炉内空气,在惰性气氛下,以5~10℃/min升温加热,在300~400℃保温120~180min,继续升温在600~800℃保温120~180min;
步骤四:保温结束后,冷却到室温,研磨黑色样品,得到目标产物VN@WN。
2.如权利要求1所述的氮化钨包覆氮化钒粉体的制备方法,其特征在于,所述的步骤二中原料混合后在玛瑙研钵中研磨30min。
3.如权利要求1所述的氮化钨包覆氮化钒粉体的制备方法,其特征在于,所述步骤二中管式炉两端的两个炉塞间隔5cm放置。
4.如权利要求1所述的氮化钨包覆氮化钒粉体的制备方法,其特征在于,所述的步骤三中排尽管式炉内空气的方法为向管内通入惰性气体,继而进行4~6次抽气补气以排尽管内空气,最后一次补气后不再抽气。
5.如权利要求1所述的氮化钨包覆氮化钒粉体的制备方法,其特征在于,所述的惰性气氛为氩气,气流速率为20~40sccm。
6.一种如权利要求1-5中任意一项所述的氮化钨包覆氮化钒粉体的制备方法制备的氮化钨包覆氮化钒粉体。
7.一种如权利要求6所述的氮化钨包覆氮化钒粉体的应用。
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101916859A (zh) * 2009-03-12 2010-12-15 巴莱诺斯清洁能源控股公司 氮化物和碳化物阳极材料
CN109280934A (zh) * 2018-09-28 2019-01-29 陕西科技大学 一种碳包覆的氮化钒电催化剂、制备方法及应用

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1318467A (en) * 1970-09-08 1973-05-31 Hollandse Metallurg Ind Billit Methods of preparation of a material containing vanadium carbonitride and or vanadium nitride
EP2723680A1 (en) * 2011-06-27 2014-04-30 Sixpoint Materials Inc. Synthesis method of transition metal nitride and transition metal nitride
CN107673317B (zh) * 2017-10-27 2020-08-21 西安建筑科技大学 一种制备氮化钒的方法
CN109319749A (zh) * 2018-10-22 2019-02-12 江苏理工学院 一种金属氮化物的制备方法
CN110624593A (zh) * 2019-09-30 2019-12-31 陕西科技大学 一种VN@Co电催化剂的制备方法
CN110560141A (zh) * 2019-09-30 2019-12-13 陕西科技大学 一种电催化功能vn@wn纳米颗粒的制备方法及应用

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101916859A (zh) * 2009-03-12 2010-12-15 巴莱诺斯清洁能源控股公司 氮化物和碳化物阳极材料
CN109280934A (zh) * 2018-09-28 2019-01-29 陕西科技大学 一种碳包覆的氮化钒电催化剂、制备方法及应用

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