Janus Mn single atoms for triggering efficient photothermal catalytic CO2 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. Additionally, 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. Resultly, the rate of CO2 methanation is 195.7 mmol g−1 h−1 with
near-unity selectivity, and the catalytic activity of 1.0%Mn/NNSO
increases by approximately 140 times compared with NNSO. This is the first
study that spin polarization effect is utilized to achieve efficient
photothermal CO2 methanation.