Combination of Co2+-immobilized covalent triazine framework and TiO2 by covalent bonds to enhance photoreduction of CO2 to CO with H2O

Pyridine CTF (CTF-Py) grafted on the surface of NH2-functionalized TiO2 (NH2-TiO2) nanoparticles gave composite TiO2@CTF-Py covalently linking the inorganic semiconductor to the nitrogen-rich porous, conjugated and coordinating organic functionality. Co2+-modified TiO2@CTF-Py was an efficient photocatalyst for the reduction of CO2 to CO with high selectivity using water as the electron donor and without exogenous photosensitizers or a sacrificial agent. The covalent connection between the semiconductors and NNN coordination group were important for this photocatalytic activity and selectivity.