Photo-Thermal Cocatalytic CO 2 Methanation over Single-Atom Alloy Clusters

Single-atom alloy (SAA) catalysts have exhibited great potential in modulating CO 2 reduction performance. However, there still exist huge challenges in the precise construction of SAA on a support. Herein, the precise immobilization of M 1 M 2 -SAA (M 1 M 2 = Pt 1 Ni, Pd 1 Ni, Pd 1 Co) onto the Zr 6 O 8 cluster of a 2D porphyrinic metal–organic framework (2D-Ni-PCN-222) was reported through a guest-metal barrier strategy. The resultant Pt 1 Ni-SAA/2D-Ni-PCN-222 displayed high reaction efficiency in photothermal catalytic CO 2 hydrogenation under atmospheric pressure (1 atm CO 2 /H 2 ) at 150 °C, giving rise to a CH 4 production rate of 1206.5 μmol·g cat –1 ·h –1 (287 mmol·g Pt –1 ·h –1 ) with larger than 99% selectivity. Mechanism studies revealed a synergistic catalysis between the 2D-Ni-PCN-222 and Pt 1 Ni-SAA in CH 4 production, where the Zr 6 O 8 cluster in 2D-Ni-PCN-222 was responsible for CO 2 adsorption and reduction to CO, while Pt 1 Ni-SAA promoted the sequential hydrogenation of CO to CH 4 . Ab initio molecular dynamic simulations further demonstrated the hydrogen spillover from Pt 1 Ni-SAA to the adjacent Zr 6 O 8 cluster, which simultaneously enhanced the kinetics of CO 2 reduction to CO at Zr 6 O 8 cluster sites and the overall CH 4 production efficiency.