Construction of TiO2 nanosheets/tetra (4-carboxyphenyl) porphyrin hybrids for efficient visible-light photoreduction of CO2

Abstract The design and construction of photocatalysts in converting CO 2 into value-added chemicals is of significant importance for addressing energy shortages and environmental pollution problems. In this work, a TiO 2 nanosheets/tetra (4-carboxyphenyl) porphyrin (TiO 2 NSs/TCPP) hybrid for photoreduction of CO 2 was developed using a simple self-assemble approach. The TCPP works as the light-harvesting unit to generate light-induced electron-hole pairs, with the connection between the TCPP and TiO 2 facilitating the electron injection to the CB of TiO 2 as well as inhibiting the recombination of photo-generated electron-hole pairs, then the highly active (0 0 1) facets of TiO 2 NSs serve as the reaction sites and efficiently convert the CO 2 molecules adsorbed on the surface of the catalysts into CO and CH 4 products. The influence of TCPP content on the photocatalytic activity was investigated. Compared to the pristine TiO 2 NSs material, the TiO 2 NSs/11.5% TCPP composite displayed a much-enhanced photocatalytic CO 2 reduction activity, which is equal to 37-fold enhancements in the CO evolution rate. Furthermore, a possible mechanism for CO 2 photoreduction over TiO 2 NSs/TCPP hybrids is proposed on the basis of the photocatalytic and photo(electro)chemical results.