Unleashing the synergistic potential of 2D-2D nanosheet based S-scheme heterojunction: Cooperative boosting of CO2 reduction to solar fuel and biomass valorization.

Abstract

Harnessing inexhaustible solar energy for CO2 valorization is substantial step toward achieving carbon-neutral energy cycle. However, CO2 conversion often exhibits slow kinetics, necessitating the utilization of sacrificial agents making the process economically unfeasible. In the ongoing quest for sustainable and economically feasible CO2 valorization, herein the photoreduction of CO2 to CO coupled with biomass-based alcohol oxidation to fine chemicals is reported via Bi2WO6/g-C3N4 (BWO/g-CN) 2D-2D nanosheet based S-scheme heterojunction. Importantly, BWO/g-CN-60 exhibits highest photocatalytic activity with CO production rate of 6.87 mmol g-1 h-1, accompanied by >98% selectivity and selective oxidation of veratryl alcohol to veratraldehyde, with notable yield of 42% in 6 h under simulated solar light. The apparent quantum yield (AQY) of 14.3% is achieved for CO production at the wavelength of 420 nm. Additionally, the formed heterostructure results in enhanced charge separation and accelerated charge transfer kinetics as validated by PL, EIS, and photocurrent studies. EPR, 13CO2 labeling, DFT studies, and various controlled experiments provided deeper insight into the mechanism of underlying photo-redox process. Thus, the current study presents a sustainable paradigm for CO2 mitigation by converting it into solar fuel, while synergistically producing the fine chemicals through effectively harnessing the full potential of charge carriers.