Synthesis of Zn Modified Carbon Nitrides Heterogeneous Catalyst for the Cycloaddition of CO₂ to Epoxides

Abstract

Various Zn modified carbon nitride (Zn‐C3N4) were facilely prepared by one‐step thermal polymerization method, and were successfully used for the chemical fixation of CO2 to epoxides producing cyclic carbonates in the presence of KI co‐catalyst. The combination of binary heterogeneous Zn‐C3N4 and KI exhibited efficient catalysis for the coupling of CO2 and epoxides. The effects of different reaction parameters, including reaction temperature, CO2 pressure, reaction time, and catalyst loading on activities were discussed. The yield of propylene carbonate (PC) could reach 99% under the optimized reaction conditions (130 oC, 2 MPa, 5 h) without additional solvent used, and the selectivity was above 99%. The catalysts showed good recycle performance and versatility for the cycloaddition of CO2 to various epoxides. The possible reaction mechanism over Zn‐C3N4/KI catalytic system was proposed. The developed Zn‐C3N4/KI catalysts exhibited attractive application as simple, effective and ecofriendly alternative catalysts for CO2 effective utilization.

Tuning Band Gap in Fe-Doped g-C3N4by Zn for Enhanced Fenton-Like Catalytic Performance

“…Figure a shows the XRD patterns of all samples, in which the diffraction peak located at 27.4° corresponds to the (002) plane of g-C 3 N 4 (JCPDS 871526). − The diffraction peak at about 13.1° (the arrow’s direction in Figure a) corresponds to the (100) plane of g-C 3 N 4 , in which the strength of the peak became poor with the Zn doping. And the diffraction peak of the (002) shifted to a small angle.…”

Nanostructured Carbon Nitrides for CO2 Capture and Conversion

“…They also doped several metals (Zn 2+ , Cd 2+ , Fe 3+ , Co 2+ , Cr 3+ , Mn 2+ ) in the g‐C 3 N 4 /silica to enhance the conversion efficiency and selectivity of the catalysts . Among them, Zn 2+ and Fe 3+ are the most effective dopants to increase the catalytic activity of the g‐C 3 N 4 /SBA‐15 for CO 2 conversion to epoxides and olefins, respectively (Figure ) . Su et al also stressed the importance of the existence of edge defects of g‐C 3 N 4 as active sites, demonstrating the superior catalytic activity of partially condensed g‐C 3 N 4 for CO 2 conversion to cyclic carbonates …”

Fabrication of a hollow sphere N,S co-doped bifunctional carbon catalyst for sustainable fixation of CO2 to cyclic carbonates

“…This is probably due to the overabundance of iodide ions which act as a hydrogen acceptor and are readily attached with pyrrolic-NH, consequently restricting the activation of CO 2 . 52 Meanwhile, the 10 mg catalyst and the 0.083 mmol co-catalyst are sufficient to increase the activity markedly.…”