Highly active carbon nanotube-supported Pd electrocatalyst for oxidation of formic acid prepared by etching copper template method

In this work, a carbon nanotube-supported Pd nano-catalyst (Pd/MCNTs) is prepared by the etching copper template strategy. Cu nanoparticles (NPs) are formed onto MCNTs first as the template and Pd NPs are then obtained through a galvanic displacement reaction between Pd ions and Cu. TEM, XRD, and XPS characterizations show the crystalline of Pd NPs with a typical diameter of 2-5 nm is homogeneously decorated onto MCNTs without aggregation. Electrochemical characterizations reveal that the Pd/MCNTs materials exhibit much higher catalytic activity for the formic acid oxidation than both conventional Pd/MCNTs and commercial Pd/Vulcan catalysts do. The improved activity is mainly attributed the fact that no surfactant is required in synthesis of the catalyst, eliminating the possible passivation of catalytic sites associated with the use of surfactant in conventional synthesis methods. In addition, the narrower distribution and better dispersion of catalyst particles, as well as no defects of MCNTs are also beneficial for the improvement in the catalytic activity. Another feature of the present synthesis method is the loading of Pd can be adjusted by varying the amount of Cu ions.