Ultrathin graphitic C3N4 nanosheets as highly efficient metal-free cocatalyst for water oxidation

•Ultrathin C3N4 nanosheets serve as efficient cocatalysts for photoelectrochemical water splitting.•The H2 generation capability is nearly 12 times with respect to the pristine BiVO4 photoanodes.•Ultrathin C3N4 could effectively transfer and store holes for water oxidation.•This work may provide an effective approach for enhancing photoelectrochemical properties.

Here, we demonstrate that ultrathin graphitic-phase C3N4 nanosheets (g-C3N4-NS) could serve as an efficient metal-free cocatalyst for improving oxygen evolution activity on nanoporous BiVO4 photoanode. More specifically, as compared with pure BiVO4 photoanode, ultrathin g-C3N4 nanolayers not only suppress the surface charge recombination of BiVO4, but also effectively transfer and store holes for water oxidation. As expected, the ultrathin graphitic-phase C3N4 cocatalyst modified BiVO4 photoanode exhibited significantly improved photocurrent density and H2 generation capability, nearly 7 and 12 times with respect to the pristine BiVO4 under the same conditions. These results demonstrate an effective approach for the design and construction of low-cost and highly efficient PEC systems.

Graphical abstractHere, we demonstrate that ultrathin graphitic-phase C3N4 nanosheets (g-C3N4-NS) could serve as an efficient metal-free cocatalyst for improving oxygen evolution activity on nanoporous BiVO4 photoanode. More specifically, as compared with pure BiVO4 photoanode, ultrathin g-C3N4 nanolayers not only suppress the surface charge recombination of BiVO4, but also effectively transfer and store holes for water oxidation. As expected, the ultrathin graphitic-phase C3N4 cocatalyst modified BiVO4 photoanode exhibited significantly improved photocurrent density and H2 generation capability, nearly 7 and 12 times with respect to the pristine BiVO4 under the same conditions. These results demonstrate an effective approach for the design and construction of low-cost and highly efficient PEC systems.Download high-res image (242KB)Download full-size image