Atomic-level Mn incorporation into Co3O4 for selective CO2 photoreduction in pure water under dilute CO2 atmosphere

The photocatalytic carbon dioxide reduction represents a promising route for solar-to-chemical energy conversion, enabling the sustainable production of carbon-neutral fuels. Achieving high selectivity toward specific products remains a major challenge due to the complex multi-electron transfer pathways and competing reaction intermediates. Herein, the Mn-doped Co 3 O 4 (MMC) photocatalysts are synthesized based on an “impregnation-pyrolysis” strategy using in situ synthesized Mn-doped ZIF-67 as a precursor. The MOF-templated approach enables uniform Mn incorporation into the Co 3 O 4 lattice while preserving a hierarchical porous architecture, thereby enhancing active-site accessibility and modulating the electronic environment of catalyst. The introduction of guest Mn effectively suppresses the competing hydrogen evolution reaction. As a result, the optimized 2MMC catalyst shows a 12.8-fold increase in CO production over undoped Co 3 O 4 and enables selective CO 2 conversion in pure water with diluted CO 2 . Photoelectrochemical characterizations reveal that guest Mn doping accelerates charge separation dynamics. In-situ irradiated X-ray photoelectron spectroscopy, in-situ Fourier transformed infrared spectra, and theoretical calculations unveil a Mn-mediated pathway that selectively promotes the formation of *CO 2 and *CO intermediates. This work provides new atomic-level insights into the selective photocatalytic conversion of CO 2 under green and sustainable conditions.