Rhenium-modified porous covalent triazine framework for highly efficient photocatalytic carbon dioxide reduction in a solid-gas system

The conversion of CO2 into valuable chemicals by means of solar energy with high efficiency is a promising alternative for decreasing greenhouse gas and solving the energy shortage. Porous covalent triazine frameworks (CTFs) have attracted considerable attention in gas adsorption and heterogeneous catalysis owing to their abundant nitrogen sites and very high thermal, chemical, and mechanical stability. In this work, a pyridine-based CTF (CTF-py, py = pyridine) derived from 2,6-dicyanopyridine is employed as a porous platform to anchor the Re carbonyl complex Re(CO)(3)Cl (Re-CTF-py), which exhibits high efficiency in the photocatalytic CO2 reduction to CO with a turnover number (TON) of 4.8; the CO evolution rate for Re-CTF-py reached 353.05 mu mol g(-1) h(-1) within 10 hours under full light irradiation in a solid-gas system. Moreover, in the solid-gas system, the single-site Re-CTF-py catalyst could prevent Re active species dimerization and leaching that lead to deactivation. This work highlights the great potential of using stable CTFs as porous platforms to anchor single active sites for heterogeneous catalysis.