Methanol-Enhanced Low-Cell-Voltage Hydrogen Generation at Industrial-Grade Current Density by Triadic Active Sites of Pt-Pd-(Ni,Co)(OH).

Methanol (ME) is a liquid hydrogen carrier, ideal for on-site-on-demand H generation, avoiding its costly and risky distribution issues, but this "ME-to-H" electric conversion suffers from high voltage (energy consumption) and competitive oxygen evolution reaction. Herein, we demonstrate that a synergistic cofunctional PtPd/(Ni,Co)(OH) catalyst with Pt single atoms (Pt) and Pd nanoclusters (Pd) anchored on OH-vacancy(V)-rich (Ni,Co)(OH) nanoparticles create synergistic triadic active sites, allowing for methanol-enhanced low-voltage H generation. For MOR, OH* is preferentially adsorbed on Pd and then interacts with the intermediates (such as *CHO or *CHOOH) adsorbed favorably on neighboring Pt with the assistance of hydrogen bonding from the surface hydrogen of (Ni,Co)(OH). The enhanced selectivity of the *CHOOH pathway, instead of *CO, sustains the MOR activity to a practically high current density. For HER, triadic Pt, Pd, and OH-vacancy sites on (Ni,Co)(OH) create an "acid-base" microenvironment to facilitate water adsorption and splitting, forming H* species on Pt and Pd, and *OH at the vacancy, to promote efficient H evolution from the asymmetric Pt and Pd sites via the Tafel mechanism. The triadic-site synergy opens new avenues for the design and synthesis of highly efficient and stable cofunctional catalysts for "on-site-on-demand" H production, here facilitated by liquid methanol.