Janus Mn single atoms for triggering efficient photothermal catalytic CO ₂ methanation through spin polarization effect

Photothermal catalysis, using sunlight as single energy source, is an ideal pattern for CO₂ reduction. Herein, Mn single atoms (SAs) are constructed on the surface of NNSO, which induces spin polarization effect, thus promoting directional transfer of photothermal electrons, and improving electron density of Mn sites and adsorption ability of CO₂. Meanwhile, Mn SAs act as new active sites enhancing the adsorption of intermediate ^*CO, thus suppressing CO production, lowering energy barriers of hydrogenation, and changing the reaction path. In addition, the hydrogen overflow energy barriers decrease under the effect of spin polarization, promoting the rapid transfer of active H from Ni atoms to Mn SAs. As a result, the rate of CO₂ methanation is 195.7 millimoles per gram per hour with near-unity selectivity, and the catalytic activity of 1.0%Mn/NNSO increases by approximately 140 times compared with NNSO. To our knowledge, this is the first study that uses the spin polarization effect to achieve efficient photothermal CO₂ methanation.