Palladium Phosphide/Black Phosphorus Heterostructures with Enhanced Ethanol Oxidation Activity and Stability

Electrocatalytic performance for the ethanol oxidation reaction (EOR) under alkaline conditions can be improved by the rational design of catalysts. Palladium phosphates have shown higher electrical conductivities and activity compared with Pd. Nevertheless, the synthesis of palladium phosphide is complex and requires a relatively high temperature. Here, we report a simple synthesis method of palladium phosphide/black phosphorus heterostructure (Pd3P/BP) with enhanced EOR activity. BP is used instead of other phosphorus sources for several reasons: (i) BP has a lone pair of electrons, which easily coordinate with the metal atoms to form palladium phosphides. (ii) As a two-dimensional layered structure material, BP has a large specific surface area, which is beneficial for the dispersion of metal nanoparticles, and thus improves the utilization rate of catalysts owing to the expanded active sites. (iii) Phosphorus species (P0) might inhibit the adsorption of CO on the catalyst surface. (iv) BP has an excellent adsorption capacity to water molecules, thereby promoting the generation of OH groups and stripping of reaction intermediates, contributing to superior EOR activity and stability of Pd3P/BP. The activity of Pd3P/BP (7411.2 mA mgPd–1) is about 9.1-fold higher than the commercial Pd/C (814.8 mA mgPd–1) and significantly higher than that of Pd3P + BP (3065.4 mA mgPd–1).