S-scheme Porous g-C3N4/Ag2MoO4 Heterojunction Composite for CO2 Photoreduction

Utilizing solar energy to achieve artificial photosynthesis of chemical fuel is prevalent in tackling excessive COemission and fossil fuel depletion. Grievous charge recombination and weak redox capability aggravate the COphotoreduction performance. Engineering tailored morphology and constructing matched heterostructure are two significant schemes to ameliorate the COphotoconversion efficiency of g-CN-based composite. Herein, a novel S-scheme ultrathin porous g-CN(UPCN)/AgMo O(AMO) composite was designed by in-situ growing tetragonal α-AMO nanoparticles(NPs)(5-30 nm) on UPCN nanosheets(NSs). The S-scheme charge transfer route endows UPCN/AMO with fast charge separation and strong redox capability, demonstrated by X-ray photoelectron spectroscopy(XPS), photoelectrochemical tests, steady-state and time-resolved photoluminescence(PL) spectra, and DFT calculations. The UPCN/AMO composite exhibits elevated COphotoreduction performance with CO and CHyield rates of 6.98 and 0.38 μmol gh, which are 3.5 and 2.9 folds higher than that of pristine UPCN, respectively. Finally, the COphotoreduction intermediates are analyzed, and the COphotoreduction mechanism is discussed. This work provides a reference for various g-CN-based composites applied in artificial photosynthesis.