Ultra-thin dealloyed PdCu bimetallene with lattice strain transformation for efficient bifunctional electrocatalysis

Abstract

Two-dimensional (2D) PdCu bimetallene (PdCu) exhibits unique structural and electronic properties, enhancing surface reactivity for crucial electrochemical reactions in energy conversion and storage. The one-pot synthesis, followed by dealloying (DA) to form DA PdCu, further enhances surface reactivity by altering the electronic structure. This process induces geometrical effects, significantly impacting surface strain and influencing selectivity and performance for (oxygen reduction reaction) ORR and (methanol oxidation reaction) MOR in an alkaline medium. The heterogeneous surface of DA PdCu with crystalline and amorphous regions and abundant surface defects, enhances active sites for improved ORR and MOR kinetics. During ORR, the DA PdCu exhibits superior mass activity (MA) of 0.62 mA mu g-1 and extended stability with a positive shift (10 mV) in half-wave potential after 20,000 cycles. Additionally, it exhibits excellent MOR-MA (3335.9 mA mg-1) with 62.3% retention after 10,000 cycles, effectively competing with reported catalysts. Theoretical studies clarify the electronic strain transformation and its influence on adsorption energies of reaction intermediates on PdCu and DA PdCu during ORR and MOR, crucially correlating with experimental findings. The alloying-dealloying process in 2D-layered PdCu is a promising strategy to enhance the structure-activity relationship for improved multifunctional electrocatalysis with greater endurance.