Light-Induced Cu+ Active Sites on 2D Conductive MOF for Enhanced Photocatalytic H2O2 Generation

Abstract

The selective photocatalytic reduction of O2 to H2O2 is an attractive route for sustainable H2O2 synthesis, yet its efficiency is often limited by the sluggish charge separation and insufficient selectivity of the two-electron oxygen reduction reaction. Here, we develop a conductive 2D Cu3(HHTP)2 metal–organic framework (MOF) in which Cu2+ sites serve as dynamic redox centers to regulate interfacial electron transfer and O2 activation. Upon photoexcitation, photogenerated electrons are preferentially transferred to Cu centers, inducing reversible reconstruction of the local Cu coordination environment. Benefiting from the extended π-conjugated framework and strong interlayer electronic coupling, the accumulated electrons can delocalize over the 2D sheets, facilitating charge separation and suppressing electron–hole recombination. Spectroscopic and theoretical investigations further reveal that the dynamically reconstructed Cu sites promote O2 adsorption and activation through electron donation from Cu d orbitals to O2 antibonding states, thereby stabilizing the O2− intermediate and favoring the two-electron reduction pathway toward H2O2. As a result, the Cu3(HHTP)2 photocatalyst achieves an H2O2 evolution rate of 3910 μmol g−1 h−1 under visible-light irradiation. These findings demonstrate that dynamically regulated Cu electronic structures provide an effective strategy for coupling charge-carrier management with selective O2 activation, offering a rational approach to the design of conductive 2D photocatalysts for efficient H2O2 photosynthesis.