Self-Disproportionation-Induced H-Adsorption/Desorption Zones in Amorphous Nickel Boride Cocatalyst for Efficient Photocatalytic Hydrogen Evolution

Hydrogen spillover is a well-established strategy for enhancing hydrogen evolution kinetics; however, in conventional binary-component catalysts, its efficiency is often limited by long diffusion distances and significant interfacial resistance. Herein, we developed an efficient intraparticle hydrogen spillover pathway in isolated amorphous nickel boride (a-NiB) cocatalysts through an amorphization-induced self-disproportionation strategy, which significantly enhances H2-evolution kinetics. Combined experimental and theoretical results demonstrate that amorphization induces uneven compression and stretching of Ni–B bonds, leading to the electronic density disproportionation of nickel active sites. This effect creates spatially separated electron-deficient and electron-rich microzones within each a-NiB nanoparticle, promoting efficient hydrogen adsorption and desorption, respectively, and thereby enabling facile intraparticle hydrogen spillover within the a-NiB cocatalyst. When coupled with CdS photocatalysts, the a-NiB cocatalyst enables vigorous visible-light-driven H2 evolution with macroscopic bubble formation and achieves a quantum efficiency of 53%. This work redefines catalyst design in amorphous materials and opens new frontiers for energy synthesis technologies.