Phase Interface Engineering of Cu₁Co Single Atom Alloy Catalysts for Enhanced Hydrogen Production from Methanol...

On-site hydrogen production from methanol decomposition has attracted interest in an energy-sustainable society, which compensates for the shortcomings of unsafe hydrogen storage and inconvenient transportation. Here, we constructed Cu₁Co single atom alloy (SAA) catalysts containing atomically dispersed Cu sites coupled with Co sites serving as intrinsic Cu-Co active sites for hydrogen production from methanol decomposition. It was demonstrated that the reduction temperatures of CuCo precursors induced the generation of distinct crystalline structures and mixed-phase interfaces of Cu₁Co SAA catalysts, thereby efficiently modulating the electronic structures of the active centers and the surface adsorption and desorption behaviors of the reactants during methanol decomposition. The as-fabricated Cu₁Co SAA catalyst featuring both the dominant hcp metallic Co phase and abundant hcp/fcc mixed-phase interfaces significantly facilitated a series of dehydrogenation processes of methanol and reaction intermediates and desorption of CO and H₂ products and achieved excellent catalytic performance, with an unprecedentedly high hydrogen production rate of 659.8 mol·mol_Cu^-1·h^-1 at complete methanol conversion. By combining structural characterization, in situ spectroscopic analysis, and density functional theory calculations, it was unveiled that atomically dispersed Cu-Co active sites both in the absolutely predominant hcp phase and at the hcp/fcc mixed-phase interfaces on Cu₁Co SAA catalysts played crucial roles in boosting hydrogen production from methanol decomposition. The present study provides a promising single atomic Cu site-mediated crystal phase and phase interface engineering strategy for developing high-performance and economical Co-based catalysts for methanol decomposition to produce hydrogen.