Photothermocatalytic CO_2 Reduction on Magnesium Oxide-Cluster-Modified Ni Nanoparticles with High Fuel Production Rate, Large Light-to-Fuel Efficiency and Excellent Durability

摘要

Highly efficient CO_2 reduction to produce fuel driven by solar energy is of greatsignificance to alleviate the greenhouse effect and realize solar energy storage.Herein, a unique nanocomposite of MgO-cluster-modified Ni nanoparticlessupported on Ni-doped MgO (MCM–Ni/Ni–MgO) is synthetized by a simpleapproach. Very high fuel production rate for H_2 and CO (78.01 and88.44mmol min~(-1)g~(-1)) as well as a large light-to-fuel efficiency (31.7%) areachieved by photothermocatalytic CO_2 reduction by CH4 on MCM–Ni/Ni–MgOmerely using focused UV–vis–IR illumination. This arises from efficient lightdriventhermocatalysis that is further enhanced by a photoactivation due tothe activation energy being considerably reduced upon the illumination. Moreimportantly, it exhibits excellent photothermocatalytic durability due to itsextremely low carbon deposition rate of 8.85×10~(-4) g_c h~(1)g~(-1)catalyst, reduced by39.2 times as compared with that of a reference sample of Ni nanoparticlessupported on Ni-doped MgO (Ni/Ni–MgO). The experimental evidences and thefunctional theory calculations reveal that the surface modification of Ni nanoparticlesby MgO cluster not only inhibits the carbon deposition side reactions ofCO disproportionation and CH_4 complete dissociation, but also significantlyaccelerates the oxidation of carbon species, thus tremendously decreasingcarbon deposition rate.