Zr-W Co-doping in BiVO4-Synergistic effect in photoelectrochemical water splitting

Photoelectrochemical response of pristine bismuth vanadate (BiVO4) is limited due to the quick electronhole pair recombination and slower water oxidation. Co-doping of BiVO4 has been investigated to enhance electron-hole pair separation as well as to improve photoelectrochemical performance. Present study, therefore, is focused on understanding the synergistic effect of zirconium (Zr) and tungsten (W) on the photoelectrochemical performance of bismuth vanadate. Series of samples with varying concentrations of W and fixed concentration of Zr are prepared. Compared to the pristine sample, sample with 4% W+3.5% Zr-BiVO4 exhibited (a) enhanced photocurrent density, (b) more roughness (18.01 nm), (c) more negative flat band potential (-0.28 V), (d) high donor density (4.0 x 1020 cm-3) and (e) least radius in nyquist plot. The depletion width and Debye length is found to be minimum for the same sample which confirms better separation of electron-hole pairs. Further, the enhancement in photoelectrochemical response can be attributed to the synergistic effect of Zr and W co-doping which augments the photon harvesting rate and separation of electron-hole pairs.

Automated summary

This study focused on the synergistic effect of zirconium (Zr) and tungsten (W) co-doping on the photoelectrochemical performance of bismuth vanadate. The co-doping resulted in enhanced photocurrent density, increased roughness, decreased flat band potential, higher donor density, and improved separation of electron-hole pairs in the sample. The enhancement in photoelectrochemical response was attributed to the synergistic effect of Zr and W co-doping which increased photon harvesting rate and separation of electron-hole pairs.