| Popis: |
The emergence of bismuth vanadate BiVO4 as one of the most promising photoanodes for solar water splitting is largely driven by the successful efforts of dopant introduction and optimization to improve its photoelectrochemical PEC performance. To this end, although less commonly used, several trivalent ions e.g., Sm3 , In3 , Gd3 that substitute Bi3 have also been demonstrated to be effective dopants, which can increase the photocurrent density of BiVO4 photoanodes. However, the main factor behind such improvement is still unclear, as various explanations have been proposed in the literature. Herein, Gd3 is introduced to substitute Bi3 in spray deposited BiVO4 films, which enables up to a 2 fold increase in the photocurrent density. Further PEC analysis suggests that Gd doping enhances the charge carrier separation in the BiVO4 films and does not affect the catalytic and optical properties. Indeed, time resolved microwave conductivity TRMC measurements reveal that the charge carrier mobility of BiVO4 is increased by 50 with the introduction of Gd while the charge carrier lifetime is unaffected. This increase of mobility is rationalized to be a result of a higher degree of monoclinic lattice distortion in Gd doped BiVO4, as evident from the X ray diffraction and Raman spectroscopy data. Overall, these findings provide important insights into the nature and the underlying role of Gd in improving the photoelectrochemical performance of BiVO4 photoanodes |
