Sulfur-doped carbon nitride functionalized PVDF membrane with S⋯H[sbnd]N bridge induced fast carrier transfer for bifunctional H2O2 and H2 production

Abstract

The utilization of green and pollution-free solar energy for photocatalytic reduction of oxygen (O2) to hydrogen peroxide (H2O2) is a highly desirable technology. In this work, sulfur (S)-doped graphitic carbon nitride (SCN) nanosheets were prepared by co-condensation of carbon nitride with thioacetamide as a sulfur source. The substitution of sp2 hybridized N atoms by S atoms created S⋯HN bridges through weak hydrogen bonds, promoting fast carrier separation and transfer. Moreover, the S-doping could effectively reduce the band gap by approximately 0.6 eV, and thereby expand photo-responsive region of SCN-based photocatalysts up to 700 nm. To gain the practicability and retrievability of prepared photocatalysts, we developed SCN-based nanomaterials functionalized polyvinylidene fluoride (PVDF) membranes for H2O2 production and H2 evolution. The optimized photocatalytic efficiency of SCN-3 reached 1491 μmol L–1 h−1 of H2O2 generation and 16.3 mmol g–1 h−1 of H2 evolution under monochromatic LED light irradiation, nearly 2–5 times higher than the state-of-art metal-free photocatalysts. These findings offer new insights into the doping regulated nanocatalysts functionalized membranes to achieve high performance in practical applications.