醇在载钯碳化钨/碳纳米管催化剂上的氧化

Alcohol Oxidation on Pd Catalyst Supported on Tungsten Carbides/Carbon Nanotubes

用交替微波法制备了碳化钨与多壁碳纳米管复合材料(WC/MWCNT),以该材料为载体制备了Pd基催化剂(Pd-WC/MWCNT),并将催化剂用于醇的催化氧化反应.结果表明,Pd-WC/MWCNT催化剂对乙醇的催化氧化活性是Pd/C催化剂的5倍.交换电流密度测量和反应活化能计算表明,Pd-WC/MWCNT催化剂对乙醇催化氧化的交换电流密度比Pd/C大两个数量级,反应活化能低一倍以上.Pd-WC/MWCNT催化剂催化氧化乙醇性能的大幅度提高是碳化钨与Pd颗粒的协同效应和碳纳米管的结构效应共同作用的结果.

A material of tungsten carbides on multiwalled carbon nanotubes （WC/MWCNT） was prepared by an intermittent microwave heating method and used as the support to load Pd nanoparticles （Pd-WC/MWCNT） for alcohol oxidation. Different surface, morphological, and electrochemical techniques were used to characterize the physical and catalytic properties of the novel catalysts. Pd/C, Pd/MWCNT, and Pd-WC/C catalysts were also prepared for comparison. The Pd-WC/MWCNT catalyst shows five times higher catalytic activity for ethanol oxidation compared to the Pd/C catalyst. Pd-WC/MWCNT is two orders higher in exchange current density and over one time lower in activation energy than the Pd/C catalyst. This proves the fast kinetics of the Pd-WC/MWCNT catalyst for the oxidation of ethanol in alkaline solution. The Pd-WC/MWCNT catalyst is also highly active for the oxidation of ethylene glycol and methanol. However, the oxidation of ethanol gives the lowest onset potential. The enhancement in the catalytic activity is believed due to synergistic effect between Pd nanoparticles and the tungsten carbides and the structure effect of the carbon nanotubes.