摘要
采用超声空化辅助法制得空心球状结构偏钨酸铵(AMT),通过固定床气-固反应,以CO/H2为还原碳化气氛在700-900℃下制备得到了介孔结构空心球状碳化钨.并再次超声处理后分解球型结构得到条状介孔碳化钨.用扫描电镜(SEM)、X射线衍射(XRD)、热重-差热分析(TG-DTA)、比表面测试(BET)和孔径分布测试(BJH)对样品进行了表征.结果表明,样品组成为单相碳化钨,且在空气中低于410℃时具有高稳定性并且具有4和22nm的双孔隙分布结构.将碳化钨粉末制成粉末微电极(PME),采用循环伏安(CV)技术研究了碳化钨在质子惰性介质中对硝基苯的电催化还原性能.结果表明,相比铂微盘电极,双孔结构碳化钨对硝基苯还原有着更好的电催化活性,在峰电位上比铂微盘正移了30mV,Ip-v1/2关系曲线显示硝基苯在粉末微电极中的还原行为受扩散控制.
Hollow spherical ammonium metatungstate（AMT）,as a precursor,was prepared by an ultrasonic method.Tungsten carbide（WC） was prepared by a gas-solid reaction in an atmosphere of CO/H2 at 700-900℃.Microspheres were fractured by ultrasonic dispersion for 1 h.X-ray diffraction（XRD）,scanning electron microscopy（SEM）,thermogravimetry-differential thermal analysis（TG-DTA）,Brunauer-Emmett-Teller（BET） surface area,and Barrett-Joyner-Halenda（BJH） pore-size distribution were used to characterize the morphology,mesoporous structure,and thermal stability of the sample.The results indicate that the sample is pure WC.The WC sample is stable in air at 410℃ and the mesopores of WC were centered at 4 nm and 22 nm.A WC powder microelectrode（WC-PME） was prepared using the prepared WC powders.The activity of WC for the electroreduction of nitrobenzene was studied by cyclic voltammetry（CV）.The results indicate that the bimodal porosity of WC-PME led to higher catalytic activity than that of a Pt micro disc electrode（Pt-MDE）.The reduction potential was 30 mV more positive than that of the Pt-MDE.The relation Ip-v1/2 showed that the electrode reaction was controlled by liquid diffusion.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2010年第9期2569-2574,共6页
Acta Physico-Chimica Sinica
基金
浙江省重大科技专项国际合作项目(2008C14040)
浙江省自然科学基金重点项目(Z4100790)
国家自然科学基金(20476097)资助~~
关键词
碳化钨
超声辅助
介孔
电催化
Tungsten carbide
Ultrasonic-assistance
Mesoporous
Electrocatalysis
