Regulating the Layer Stacking Configuration of CTF-TiO2Heterostructure for Improving the Photocatalytic CO2Reduction

Herein, covalent triazine frameworks in eclipsed AA and staggered AB stacking modes are respectively used for the in-situ growth of TiO2, and two heterostructures are obtained. Due to the highly organized stacking of the molecular layer in CTF-AA that strengthens the interlayer interaction, the light absorption and carrier migration of CTF-AA/TiO2are both enhanced in comparison to those of its component or CTF-AB/TiO2. Correspondently, the photocatalytic CO2reduction reaction (CO2RR) of CTF-AA/TiO2proffers 9.19 μmol·g–1·h–1CH4and 2.32 μmol·g–1·h–1CO production, about 9.2 and 4.3 times greater than that of pristine TiO2, respectively. Even though the innate photoresponse of the triazine unit endows CTF-AB/TiO2with augmented light capturing, its photocatalytic CO2conversion is relatively insignificant. According to the analyses of the planar-averaged electron density difference and Bader charge, the unproductive CO2efficiency might be due to the insufficient interfacial electron transfer from TiO2to CTF-AB. Given that the ΔG(−3.22 eV) of CHO intermediate generation is lower than that of CO desorption (−1.23 eV), the reaction tends to further generate CH4other than yielding CO. This study could shed fresh light over the reasonable design of effective photocatalytic heterostructures.