Trimetallic PdCuIr nanocages as efficient bifunctional electrocatalysts for polyalcohol oxidation and hydrogen evolution reaction

Despite amounts of researches in recent years, it is still desirable but challenging to fabricate well-defined bifunctional catalysts with high performance towards alcohol oxidation and hydrogen evolution reaction (HER). Herein, a unique trimetallic PdCuIr catalyst with a nanocage (NC) structure is synthesized to be an excellent bifunctional catalyst by a seed-mediated growth strategy. The as-prepared PdCuIr NC catalyst exhibits remarkably enhanced mass activity and durability towards glycerol oxidation reaction (GOR) and ethylene glycol oxidation reaction (EGOR) as compared with commercial Pd/C catalyst. The optimal Pd58Cu32Ir10 NCs show electrocatalytic activities of 2565.79 mA mg(Pd)(-1) and 4498.30 mA mg(Pd)(-1) for GOR and EGOR, respectively. Meanwhile, the well-defined PdCuIr NC catalyst also displays outstanding electrocatalytic performance for HER, and the overpotential of Pd58Cu32Ir10 NCs only requires 54 mV to arrive at a current density of 10 mA cm(-2), along with excellent electrochemical durability. The enhancement of electrocatalytic properties is attributed to the introduction of Cu and Ir atoms, which could modify the electronic structure of Pd to optimize the adsorption of reactants and intermediates. Moreover, the unique NC structure also significantly increases the number of reaction active sites as well as accelerates mass transport. Following this method, the trimetallic PdCuRu NCs and PdCuRh NCs are also synthesized. This work not only offers a general strategy for the fabrication of well-defined ternary alloy nanocatalysts, but also presents an advanced class of bifunctional catalysts for polyalcohol electrooxidation and HER. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.