Unlocking a Parallel Dual-Path Mechanism for Photothermal Synergistic Catalytic Methanol Reforming over Bifunctional Cu−Cu/Cu−Zn Coordination Sites

Photothermal reforming of methanol offers a transformative approach for efficient on-site H 2 production. However, its advancement is restricted by the structural and functional ambiguity of active sites, as well as the elusive nature of photothermal effects-mediated reaction mechanisms. Here, atomically defined CuZn bifunctional catalysts are engineered via hydroxide-targeted reduction strategy, which enables regulated active phase segregation of distinct metallic Cu−Cu and alloyed Cu−Zn coordination domains by fine tuning reactive metal-support interactions. Experimental and theoretical investigations reveal a definitive functional decoupling, where electron-rich Cu−Cu sites facilitate CH 3 OH dehydrogenation, and oxophilic Cu−Zn sites promote H 2 O dissociation. These specific coordination sites effectively activate the reactants through orbital hybridization and electron back donation. Crucially, isotope analysis combined with in situ spectroscopy reveals that beyond the prevalent formate pathway, photothermal synergistic effects unlock a parallel methyl formate-mediated pathway by promoting a Cannizzaro-type coupling of CH 2 O * intermediates, which was kinetically limited in pure thermocatalysis. Such a parallel dual-path mechanism contributes a high H 2 production of 200.8 mmol g −1 h −1 over bifunctional CuZn catalysts at 200 °C with UV light irradiation, representing an advanced level for Cu-based catalysts under mild photothermal conditions. This study elucidates the atomic-level structure-activity relationship, and offers fundamental insights into harnessing photothermal synergistic effects.