TY - JOUR
T1 - A Type II n-n staggered orthorhombic V2O5/monoclinic clinobisvanite BiVO4 heterojunction photoanode for photoelectrochemical water oxidation
T2 - Fabrication, characterisation and experimental validation
AU - Yaw, Chong Siang
AU - Ruan, Qiushi
AU - Tang, Junwang
AU - Soh, Ai Kah
AU - Chong, Meng Nan
N1 - Funding Information:
Prof. MN Chong is highly indebted to the Royal Society-Newton Advanced Fellowship (Reference No.: NA150418) awarded to him in collaboration with Prof. J Tang at the University College London (UCL) Solar Energy & Advanced Materials group.
Publisher Copyright:
© 2019 Elsevier B.V.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2019/5/15
Y1 - 2019/5/15
N2 - Conventional photoanode using a singular semiconductor material is not technically viable for photoelectrochemical (PEC) water oxidation owing to the properties relating to its wide band gap, sluggish charge mobility, as well as poor separation and rapid recombination of photogenerated charge carriers. The main aim of this study was to fabricate an n-n heterojunction photoanode of V2O5/BiVO4 via a facile electrodeposition synthesis method in order to overcome the technical bottlenecks encountered in conventional singular photoanode structures. Additionally, the synergistic effect of band potentials matching and conductivity difference between BiVO4 and V2O5 were studied using LSV, IMPS, EIS, HR-TEM, XRD, XPS, Raman and ultraviolet-visible spectroscopies. This was followed by the performance evaluation of the light-induced water splitting using a standard three-electrode assembly PEC cell under 1.5 AM solar simulator. Results showed that the V2O5/BiVO4 heterojunction photoanode achieved a significantly improved photocurrent density of 1.53 mA/cm2 at 1.5 V vs Ag/AgCl, which was a 6.9-fold and a 7.3-fold improvement over the individual pristine BiVO4 (0.22 mA/cm2) and V2O5 (0.21 mA/cm2), respectively. The improvement was attributed to the lower charge resistances at the FTO/semiconductor, semiconductor/FTO and semiconductor/electrolyte interfaces as well as the fast transit time (τ) of 6.4 ms for photo-injected electrons in the V2O5/BiVO4 heterojunction photoanode. Finally, the experimental results were used to reconstruct a theoretical band diagram in validating the heterojunction alignment between V2O5 and BiVO4 as well as in elucidating the photogenerated charge carriers transfer mechanism in the V2O5/BiVO4 heterojunction photoanode.
AB - Conventional photoanode using a singular semiconductor material is not technically viable for photoelectrochemical (PEC) water oxidation owing to the properties relating to its wide band gap, sluggish charge mobility, as well as poor separation and rapid recombination of photogenerated charge carriers. The main aim of this study was to fabricate an n-n heterojunction photoanode of V2O5/BiVO4 via a facile electrodeposition synthesis method in order to overcome the technical bottlenecks encountered in conventional singular photoanode structures. Additionally, the synergistic effect of band potentials matching and conductivity difference between BiVO4 and V2O5 were studied using LSV, IMPS, EIS, HR-TEM, XRD, XPS, Raman and ultraviolet-visible spectroscopies. This was followed by the performance evaluation of the light-induced water splitting using a standard three-electrode assembly PEC cell under 1.5 AM solar simulator. Results showed that the V2O5/BiVO4 heterojunction photoanode achieved a significantly improved photocurrent density of 1.53 mA/cm2 at 1.5 V vs Ag/AgCl, which was a 6.9-fold and a 7.3-fold improvement over the individual pristine BiVO4 (0.22 mA/cm2) and V2O5 (0.21 mA/cm2), respectively. The improvement was attributed to the lower charge resistances at the FTO/semiconductor, semiconductor/FTO and semiconductor/electrolyte interfaces as well as the fast transit time (τ) of 6.4 ms for photo-injected electrons in the V2O5/BiVO4 heterojunction photoanode. Finally, the experimental results were used to reconstruct a theoretical band diagram in validating the heterojunction alignment between V2O5 and BiVO4 as well as in elucidating the photogenerated charge carriers transfer mechanism in the V2O5/BiVO4 heterojunction photoanode.
KW - Bismuth vanadate
KW - Charge separation
KW - n-n Heterojunction
KW - Photoelectrocatalysis
UR - http://www.scopus.com/inward/record.url?scp=85060750937&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2019.01.179
DO - 10.1016/j.cej.2019.01.179
M3 - Article
AN - SCOPUS:85060750937
SN - 1385-8947
VL - 364
SP - 177
EP - 185
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
ER -
