Strain effect induced Pd nanoparticles decorated Pd2+-doped Co3O4 nanosheets for efficient electrocatalytic ethanol oxidation and oxygen reduction reactions

Reactive metal-support interaction (RMSI) is an effective means of inducing surface strain and charge transfer in catalysts, which further enhances electrochemical activity and modulates reaction pathways. Nevertheless, the precise synthesis of nanomaterials with tunable strain and unique morphology remains a challenge. In this work, we have synthesized Pd nanoparticles decorated Pd2+- doped Co3O4 nanosheets (Pd7.4%/Co3O4) by a NaBH4 reduction method, which exhibit excellent performance for ethanol oxidation reaction (EOR) and oxygen reduction reaction (ORR). The introduction of the Pd into the Co3O4 by the means of elemental doping and nanoparticle decoration, and the resulting lattice strain and electron redistribution are responsible for the improved performance. Meanwhile, Pd7.4%/Co3O4 has a relatively low d-band center that reduces the adsorption energy of reaction intermediates to improve reaction selectivity and eliminate EOR toxic intermediates, ultimately promoting reaction kinetics. This work demonstrates a simple and effective strategy to manipulate lattice strain and electronic coupling and provides a novel and advanced way for the development of low-cost and highquality direct ethanol fuel cells (DEFCs) catalysts.