Evolution of palladium/copper oxide-titanium dioxide nanostructures by dealloying and their catalytic performance for methanol electro-oxidation

A direct methanol fuel cell (DMFC) anode based on a Pd/CuO-TiO2 composite, prepared by a one-pot procedure that involved dealloying an amorphous Ti-Cu-Pd alloy, exhibited high electrocatalytic activity in methanol. A single-crystalline rutile TiO2 nanoneedle film was directly grown on the nanoporous Pd/CuO for the first time. The morphology and density of the TiO2 nanoneedles could be controlled by changing the dealloying process parameters, such as HCl concentration and growth time. Ti in the amorphous Ti-Cu-Pd alloy was separated by selective dissolution during the dealloying process, and served as the source of TiO2 in the chemical synthesis. Because of their bifunctional mechanism, TiO2 needles were explored as auxiliary materials for the nanoporous Pd/CuO catalyst, yielding a current density of 381 mA mg−1, which was about 7.04 and 1.41 times higher than that of pure nanoporous Pd and Pd/CuO catalysts, respectively. Additionally, the catalytic performances and mechanisms for various concentrations of as-prepared catalysts in methanol and NaOH solutions were investigated.