Visible-light-driven photocatalytic hydrogen production on defective, sulfur self-doped g-C3N4 nanofiber fabricate via electrospinning method

This study scrutinized the impact of the sulfur (<1.0 wt. %), calcination temperature (550-650 oC), and structure (bulk, nanofiber) on the texture-photoelectronic characters, crystallinity, and performance of the fabricated g-C3N4 over H2 evolution rate (HER). Sulfur self-doped g-C3N4 nanofiber with porous structure and carbon vacancies (labeled as SCNF) was fabricated via an electrospinning process followed by suitable thermal treatment. The formation mechanism was proposed. Compared to S-doped g-C3N4 bulk, the S-doped g-C3N4 nanofiber showed a 2.84 folds improvement in HER (ca. 632 mu mol/h.g) under identical testing conditions. The enhancement for the photocatalytic activity of SCNF samples related to the photoelectronic-texture feature, which enhanced the charge separation efficiency, suppressed the recombination rate, and improved the Vis-light harnessing capability. Interestingly, the modified g-C3N4 showed the ability to interact with long wavelengths up to 710 nm. As the synthesis method for SCNF with high performance is simple, the SCNF can be envisioned as applicable in solar energy conversion and environmental remediation, which is beneficial to the environment and human development.

Automated summary

This study investigated the effects of sulfur, calcination temperature, and structure on the texture-photoelectronic characters and performance of g-C3N4. S-doped g-C3N4 nanofiber showed a significant improvement in the H2 evolution rate compared to S-doped g-C3N4 bulk. The enhanced photocatalytic activity of SCNF samples was attributed to their unique photoelectronic-texture feature.