Zn and N co-doped porous carbon nanosheets for photothermally-driven CO2 cycloaddition

Solar energy is considered as the cleanest, cheapest, and most sustainable energy source, and CO 2 cycloaddition that is drove by solar energy has unique advantages in the aspect of energy and environmental. Therefore, Zn and N co-doped porous carbon nanosheets (ZNCs), which were synthesized by a simple one-step pyrolysis method, as catalysts and photothermal material to photothermally drive cycloaddition of CO 2 . The prepared ZNCs show graphene-like layered structure, uniformly distributed Lewis acid (Zn atoms) sites and Lewis base (N atoms) sites, full spectrum absorption and high photothermal conversion efficiency. More importantly, ZNCs have a higher catalytic efficiency than traditional heating methods because it can be quickly in-situ heated by light, hence the yield of cyclic carbonate reached 91.1% (0.1 MPa CO 2 , 1000 mW·cm −2 full-spectrum irradiation, 12 h). ZNCs were recycled five times without significant reduction in catalytic efficiency, and have high activity to other series of epoxides. A possible CO 2 cycloaddition mechanism which is catalyzed by ZNCs is proposed, including the step of adsorption, ring opening, insertion and cyclic carbonates formation.