Lattice-engineered PdCu bimetallene for superior electrocatalytic water splitting via electrochemical dealloying

Achieving efficient electrocatalysis for sustainably converting energy demands precise tuning of the structure-activity relationship of catalysts. Herein, we introduce a novel strategy for optimizing 2D PdCu bimetallene layers (BMLs) via an electrochemical dealloying (DA) process, modulating the electronic structures via lattice strain distortion. This boosts heterojunction surface activity and accelerates reaction kinetics, establishing DA PdCu BMLs as potential electrocatalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. At 10 mA cm⁻², the DA PdCu BMLs achieve low overpotentials of 301 (OER) and 221 mV (HER) on a glassy carbon disc electrode. On carbon cloth electrodes in 1 M KOH, the DA PdCu BMLs achieve overpotentials of 177 (OER) and 127 mV (HER), outperforming the untreated PdCu BMLs that achieve 237 and 245 mV, respectively. Stability tests over 10,000 cycles reveal minimal degradation, with only a 3-mV shift in the OER overpotential, unlike the 22 and 54 mV for the PdCu BMLs and Pd/C, respectively. The PdCu and DA PdCu BMLs require 189 and only 161 mV to reach 10 mA cm⁻² for the HER, respectively. Theoretical calculations show that electronic modulation alters OER and HER intermediate adsorption on PdCu and DA PdCu BMLs, which is in line with experimental observation. This study underscores the importance of electronic modulation and defect engineering in optimizing catalytic performance and stability for water splitting.