Anchoring nanosized Pd on three-dimensional boron- and nitrogen-codoped graphene aerogels as a highly active multifunctional electrocatalyst for formic acid and methanol oxidation reactions†
Both direct formic acid fuel cells (DFAFCs) and direct methanol fuel cells (DMFCs) are promising power-generation technologies for various electronic devices, while their large-scale commercial applications are largely precluded by the lack of advanced noble metal catalysts with high activity and acceptable cost. Herein, we report a simple and scalable strategy to prepare nanosized Pd crystals anchored on three-dimensional (3D) boron- and nitrogen-codoped graphene aerogels (Pd/BNG) as multifunctional electrocatalysts for formic acid and methanol oxidation reactions. The resulting Pd/BNG catalyst possesses a series of distinctive structural merits adapted to the anode fuel cell catalytic systems, such as large specific surface areas, 3D interconnected porous frameworks, uniform Pd distribution, abundant B and N active sites, and excellent electrical conductivity. Compared with the conventional Pd/carbon black and Pd/graphene catalysts, the newly designed 3D Pd/BNG architecture exhibits dramatically enhanced electrocatalytic performance, including large electrochemically active surface areas, high mass activity, and good long-term stability. Density functional theory calculation further discloses that there is a strong electronic interaction between Pd and the BNG substrate, which effectively enhances the antitoxic ability of Pd/BNG toward CO intermediates and thereby promotes the electrocatalytic reaction kinetics.