Constructing frustrated Lewis acid–base Cu···N pairs on Pd metallene toward efficient oxygen reduction reaction

High-performance oxygen reduction reaction (ORR) activity is an essential indicator of efficient electrocatalysts for rechargeable Zn–air batteries (ZABs). Metallenes have attracted considerable attention in energy and catalysis due to their unique properties. The modulation of metallenes through engineering the lattice strain, electronic structure, and crystallinity, etc., offers an opportunity but still challenging. In this study, we report a Pd metallene (Pdene) catalyst with abundant frustrated Lewis pairs (FLPs) on the exposed Pd facets, in which the introduced Cu and N atoms served as Lewis acid and base sites, respectively. The interfacial Lewis acid–base Cu···N pairs effectively decreased the intermediate adsorption, contributing to the improvement of catalytic activity and durability. As expected, the optimal Cu 1 /N-Pdene catalyst exhibits exceptional ORR performance with a half-wave potential of 0.93 V, surpassing the benchmark Pt/C. Moreover, theoretical calculations reveal the Cu···N FLP can optimize charge redistribution and d-band center of Pd, thus reducing the ORR barrier and accelerating ORR kinetics. With Cu 1 /N-Pdene as the air electrode, both aqueous and all-solid state ZABs deliver remarkable battery performance, with high open circuit voltage, power density, and excellent stability. This work not only highlights the crucial role of Lewis acid-base pairs in metallenes for ORR, but also provides a strategy to regulate the electronic structure of Pdene.