Facile synthesis of 3D nanoporous Pd/Co2O3 composites with enhanced catalytic performance for methanol oxidation

To simultaneously reduce noble metal Pd usage and enhance electrocatalytic performance for methanol oxidation, Pd/Co2O3 composites with ultrafine three-dimensional (3D) nanoporous structures were designed and synthesized by simple one-step dealloying of a melt-spun Al-Pd-Co alloy with an alkaline solution. Their electrocatalytic activity in alkaline media was determined by a Versa-STAT MC workstation. The results indicate that the typical sizes of the ligaments and pores of the composites were approximately 8-9 nm. The Co2O3 was uniformly distributed on the Pd ligament surface. Among the as-prepared samples, the nanoporous Pd/Co2O3 composite generated from dealloying of the Al84.5Pd15CoO0.5 alloy had the best electrocatalytic activity, and its activity was enhanced by approximately 230% compared with the nanoporous Pd from dealloying of Al85Pd15. The improvement of the electrocatalytic performance was mainly attributed to the electronic modification effect between Pd and Co as well as the bifunctional mechanism between Pd and Co2O3.