Electrospinning Preparation of Nanostructured g‑C<sub>3</sub>N<sub>4</sub>/BiVO<sub>4</sub> Composite Films with an Enhanced Photoelectrochemical Performance

Nanostructured g-C<sub>3</sub>N<sub>4</sub>/BiVO<sub>4</sub> composite films with an enhanced photoelectrochemical (PEC) performance have been fabricated via the facile electrospinning technique. The g-C<sub>3</sub>N<sub>4</sub> nanosheets can not only form heterojunctions with BiVO<sub>4</sub> but also prevent the agglomeration of BiVO<sub>4</sub>, helping the formation of nanostructures. The as-prepared g-C<sub>3</sub>N<sub>4</sub>/BiVO<sub>4</sub> films exhibit good coverage and stability. The PEC performance of the g-C<sub>3</sub>N<sub>4</sub>/BiVO<sub>4</sub> films is much more enhanced compared with that for individual BiVO<sub>4</sub> films because of the enhanced electron–hole separation. The photocurrent density is 0.44 mA/cm<sup>2</sup> for g-C<sub>3</sub>N<sub>4</sub>/BiVO<sub>4</sub> films at 0.56 V in the linear sweep current–voltage test, over 10 times higher than that of individual BiVO<sub>4</sub> films (0.18 mA/cm<sup>2</sup>). The effects of the preparation conditions including the g-C<sub>3</sub>N<sub>4</sub> content, collector temperature, calcination temperature, and electrospinning time on the PEC performance were investigated, and the reasons for the effects were proposed. The optimal preparation condition was with 3.9 wt % g-C<sub>3</sub>N<sub>4</sub> content in the electrospinning precursor, 185 °C collector temperature, 450 °C calcination temperature, and 40 min electrospinning time. The excellent PEC performance and the facile preparation method suggest that the g-C<sub>3</sub>N<sub>4</sub>/BiVO<sub>4</sub> films are good candidates in energy and environmental remediation area.