Interfacial asymmetry-driven CO2 photoreduction with nearly 100 % CO selectivity

The photocatalytic reduction of CO 2 with H 2 O is a promising route for solar-to-chemical energy conversion but remains limited by the inertness of CO 2 and poor product selectivity. Here, we construct a Mn-OVs-Ti asymmetric heterostructure by integrating oxygen-vacancy-rich MnO 2 nanosheets with TiO 2 nanoparticles to modulate interfacial charge distribution. The resulting built-in electric field enhances CO 2 adsorption, stabilizes the COOH* intermediate, and promotes directional charge migration. As a result, the 50-MT catalyst delivers a CO evolution rate of 177.71 μmol g −1 within 5 h with nearly 100 % selectivity in pure water under simulated sunlight. In situ DRIFTS, EPR, and DFT analyses confirm the strengthened CO 2 activation and lowered reaction barriers at the Mn-OVs-Ti interface. This work demonstrates the effectiveness of asymmetric interfacial engineering in tuning photoredox pathways and provides a general strategy for developing efficient and selective CO 2 reduction photocatalysts.