Lignin-mediated atomic coordination engineering of Ru nanoclusters with self-optimized Mott-Schottky interfaces for...

The global transition toward carbon neutrality urgently demands scalable green hydrogen technologies driven by renewable energy. While water electrolysis represents a key pathway, current anion exchange membrane technologies face critical limitations in catalyst stability and efficiency, particularly in terms of ruthenium-based cathodes for the alkaline hydrogen evolution reaction (HER). Conventional synthesis methods frequently encounter irreversible nanoparticle aggregation due to weak metal-ligand coordination, significantly compromising catalytic durability. We present a groundbreaking supramolecular assembly strategy utilizing lignin's polyphenolic architecture to construct robust lignin-metal supramolecular framework (MSF@Lignin), achieving unparalleled dispersion of Ru active sites. Subsequent pyrolysis induces synergistic structural coupling between carbonized lignin matrices and Ru nanoclusters, forming electron-redistributed Mott-Schottky interfaces that drastically enhance charge transfer kinetics. The anion exchange membrane-water electrolyzer (AEMWE) device using Ru@OALC as the cathode achieved an industrial-grade current density of 0.5 A·cm^-2 at an extremely low cell voltage of 1.69 V at 25 °C and operated stably for 800 h at a slow voltage decay of 0.1 mV·h^-1. The structure-activity relationship of Ru@OALC was elucidated. In situ monitoring of adsorption effects during HER reaction by electrochemical quartz crystal microbalance was proposed for the first time, and the dissociation of H₂O molecules was visualized as a rate-limiting step for alkaline HER. This research underscores lignin's potential in developing stable electrocatalysts, advancing electrocatalytic materials, and contributing to sustainable hydrogen production for a cleaner energy future.