Fabrication of noble-metal-free copper-doped TiO2 nanofibers synergized with acetic acid-treated g-C3N4 nanosheets for enhanced photocatalytic hydrogen evolution

Abstract

The combination of copper-doped TiO2 nanofibers (Cu-TiO2 NFs) with acetic acid-treated graphitic carbon nitride (g-C3N4) provided an efficient photocatalyst for hydrogen (H2) evolution. Nanosheets of g-C3N4 (0.2, 0.3, and 0.4 wt%) integrated with Cu-doped TiO2 NFs displayed improved photocatalytic H2 evolution efficiency. The highest H2 evolution of 1.30 mmol/g was recorded for 0.3 wt% g-C3N4 coated on Cu-TiO2 NFs, which was 18.64-fold higher than the H2 evolution of g-C3N4 alone and 8.15-fold higher than the H2 evolution of pure TiO2 NFs. As indicated by different experimental characterizations, the incorporation of photosensitizers, including copper and g-C3N4 nanosheets, enabled enhanced photoresponse and successful separation of charge carriers. Furthermore, the synergistic effect between 1D and 2D structures resulted in heterojunction formation which helped in superior charge separation consequently enhancing photocatalytic H2 evolution. Thus, this work can provide new ideas and insights for the synthesis of non-precious metal-based photocatalysts.