Photonic Boosting of Lattice Oxygen Mobility in Rh–Mn/CoAlOx Heterostructure Catalysts to Enhanced CO-SCR Catalytic Performance

Developing efficient low-temperature selective catalytic reduction (CO-SCR) catalysts remains a key challenge in reducing nitrogen oxide (NO_x) emissions. Here, we report a photothermal-enhanced Rh-Mn/CoAlO_x heterostructure catalyst that achieves excellent NO conversion (more than 90% at 140 °C) and N₂ selectivity (>80%) under visible to infrared light irradiation. By integration of highly dispersed Rh units with Mn clusters onto a hydrotalcite-derived CoAlO_x support, the catalyst exhibits synergistic light absorption and dynamic lattice oxygen migration capabilities. Through combined analysis using in situ DRIFTS, XAFS, XPS, EPR, and other techniques, we reveal that Mn doping induces numerous oxygen vacancies and promotes electron transfer between Rh and Mn, facilitating lattice oxygen activation via a mechanism similar to the Mars-van Krevelen mechanism. Light exposure reduces the activation energy and, according to Arrhenius analysis and NO-TPD results, accelerates the decomposition of nitrate intermediates and enhances the conversion rate of nitrous oxide to N₂. Density functional theory (DFT) calculations confirm that N₂O is more likely to be generated at the Rh-Mn interface, demonstrating its enhanced low-temperature activation ability for NO. This study innovatively enhances the catalytic performance of CO-SCR using light, providing a sustainable method for reducing low-energy NO_x emissions.