Nonequilibrium Electronic Response Modes Govern Chemical Reactivity under Illumination

While nonequilibrium electronic configurations generated under illumination are widely recognized as central to photocatalysis, how they govern catalytic reaction energetics remains poorly understood. Here, we develop a delta self-consistent field (ΔSCF)-based theoretical framework to investigate catalytic reaction energetics under nonequilibrium electronic conditions and demonstrate it using H2 dissociation, a fundamental hydrogen-activation step, at doped Cu/ZnO photocatalytic interfaces. By constructing and continuously following metastable nonequilibrium electronic configurations along the reaction coordinate, we directly establish their connection with catalytic reaction energetics. We show that illumination-induced catalytic responses are governed not simply by the nonequilibrium electronic configurations accessible under illumination, but by how the resulting electronic perturbations couple to chemically relevant interactions as the reaction proceeds. Depending on catalyst composition, these perturbations give rise to three distinct nonequilibrium response modes, leading to dopant-dependent promotion or inhibition of H2 activation. The present work establishes a mechanistic framework linking evolving nonequilibrium electronic configurations, excitation-induced response modes, and catalytic energetics, providing general design principles for tailoring heterogeneous photocatalysis through nonequilibrium electronic-structure engineering.