热处理对电沉积Ni-W-P合金催化析氢性能的影响  

Effect of Heat Treatment on the Electrocatalytic Activity of Electrodeposited Ni-W-P Alloy for Hydrogen Evolution Reaction

作　　者：张卫国[1] 刘洋[1] 李贺[1] 姚素薇[1] 

机构地区：[1]天津大学化工学院杉山表面技术研究室,天津300072

出　　处：《催化学报》2006年第11期967-970,共4页

基　　金：天津市科技攻关项目(023106111);天津市自然科学基金项目(033602411)资助.

摘　　要：采用电沉积方法制备了Ni-W-P合金镀层,并在不同温度下进行热处理,通过极化曲线和交流阻抗谱研究了热处理温度对Ni-W-P合金催化析氢性能的影响.结果表明,经200℃热处理的Ni-W-P合金电极析氢过电位最低,在电流密度为8·0mA/cm2时,其析氢过电位较未经热处理的Ni-W-P合金电极减小约110mV.该样品的析氢电化学反应电阻为17·1Ω·cm2,交换电流密度约为未经热处理的Ni-W-P合金的5·0倍,析氢反应表观活化能降低.差示扫描量热法、X射线衍射和扫描电镜测试结果表明,Ni-W-P合金镀层经200℃热处理后发生低温结构弛豫,平均晶粒尺寸由1·1增大到2·8nm,合金由非晶结构转变为纳米晶结构,镀层表面形成宽度约为0·2μm的微裂纹.Ni-W-P alloy deposits were prepared by electrodeposition and heat treatment at different tempera tures. Cathodic polarization curves and electrochemical impedance spectroscopy were used to study the influence of heat treatment on the electrocatalytic activity of the electrodeposited Ni-W-P alloy for the hydrogen evolution reaction （HER）, The results demonstrated that, after heat treatment at 200 ℃, Ni-W-P alloy electrodes exhibited the highest electrocatalytic activity for HER and the overpotential was lowered by 110 mV at 8.0 mA/cm^2 compared with the Ni-W-P alloy without heat treatment. The electrochemical reaction resistance for HER of the Ni-W-P alloy heat-treated at 200 ℃ was 17.1 Ω· cm^2 and its exchange current density was 4.0 times higher than that of the Ni-W-P alloy without heat treatment. The increase in electrocatalytic activity of Ni-W-P alloys can be attributed to the increase in the real surface area and the decrease in the apparent energy of activation. The surface morphology and microstructure of the Ni-W-P alloy electrode were characterized by differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy. The average grain size of Ni-W-P alloy an- nealed at 200 ℃ increased from 1.1 to 2.8 nm and its structure changed from amorphous to nano crystalline.

关 键 词：电沉积 镍 钨 磷 合金 热处理 电催化 氢 

分 类 号：O643.36[理学—物理化学]