Construction of 2D/2D α-Fe2O3/g-C3N4 Z-scheme photocatalysts with SnO2 as an energy platform for directed charge transfer in cascade heterojunction: Photocatalytic CO2 reduction and pollutant degradation

Developing an efficient visible-light-driven photocatalysts for conversion of atmospheric CO2 into valuable fuels is a promising strategy to mitigate the escalating greenhouse gas, environmental, and energy crisis. This study presents an innovative design for a cascade Z-scheme comprising of dimensional matched SnO2-α-Fe2O3/g-C3N4 (SO-FO/CN) nanosheets heterojunction. In this configuration, SnO2 functions as an optimal energy platform that not only facilitates charge transfer and separation but also sustains sufficient thermodynamic energy for redox reactions and inhibits the undesired type-II charge transfer pathway. The optimized cascade Z-scheme exhibits a remarkable 20-fold improved photoactivity for CO2 conversion to CH4 and CO compared to bare g-C3N4 (CN). It also shows significantly improved photocatalytic activity for the degradation of toxic organic pollutants, 2,4-dichlorophenol (2,4-DCP) ∼6.6-fold and bisphenol A (BPA) ∼4.2-fold, respectively. The improved photocatalytic activity results from effective charge separation facilitated by the Z-scheme, along with a favorable energy platform and extended charge lifetime. This innovative strategy, which utilize an energy platform, presents a promising approach for designing an efficient Z-scheme heterojunction photocatalysts for solar-to-fuel conversion and pollutant degradation.