Single‐Atom Titanium on Mesoporous Nitrogen, Oxygen‐Doped Carbon for Efficient Photo‐thermal Catalytic CO2 Cycloaddition by a Radical Mechanism

Abstract

AbstractDeveloping efficient and earth‐abundant catalysts for CO2 fixation to high value‐added chemicals is meaningful but challenging. Styrene carbonate has great market value, but the cycloaddition of CO2 to styrene oxide is difficult due to the high steric hindrance and weak electron‐withdrawing ability of the phenyl group. To utilize clean energy (such as optical energy) directly and effectively for CO2 value‐added process, we introduce earth‐abundant Ti single‐atom into the mesoporous nitrogen, oxygen‐doped carbon nanosheets (Ti−CNO) by a two‐step method. The Ti−CNO exhibits excellent photothermal catalytic activities and stability for cycloaddition of CO2 and styrene oxide to styrene carbonate. Under light irradiation and ambient pressure, an optimal Ti−CNO produces styrene carbonate with a yield of 98.3 %, much higher than CN (27.1 %). In addition, it shows remarkable stability during 10 consecutive cycles. Its enhanced catalytic performance stems from the enhanced photothermal effect and improved Lewis acidic/basic sites exposed by the abundant mesopores. The experiments and theoretical simulations demonstrate the styrene oxide⋅+ and CO2⋅− radicals generated at the Lewis acidic (Tiδ+) and basic sites of Ti−CNO under light irradiation, respectively. This work furnishes a strategy for synthesizing advanced single‐atom catalysts for photo‐thermal synergistic CO2 fixation to high value products via a cycloaddition pathway.