Hydrothermal synthesis of titanium-supported nanoporous palladium–copper electrocatalysts for formic acid oxidation and oxygen reduction reaction

Nanoporous Pd and binary Pd-Cu particles were prepared by a hydrothermal method using ethylene glycol as a reduction agent and they were directly immobilized on Ti substrates named as Ti-supported Pd-based catalysts. Their electrocatalytic activity for formic acid oxidation and oxygen reduction reaction (ORR) in alkaline media was examined by voltammetric techniques. Among the as-prepared catalysts, nanoPd81Cu19/Ti catalyst presents the highest current density of 39.8 mA/cm2 at −0.5 V or 66.4 mA/cm2 at −0.3 V for formic acid oxidation. The onset potential of ORR on the nanoPd81Cu19/Ti catalyst presents an about 70 mV positive shift compared to that on the nanoPd/Ti, and the current density of ORR at −0.3 V is 2.12 mA/cm2, which is 3.7 times larger than that on the nanoPd/Ti.