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Title: Undoped and Ni-doped CoO x surface modification of porous BiVO 4 photoelectrodes for water oxidation

Surface modification of photoanodes with oxygen evolution reaction (OER) catalysts is an effective approach to enhance water oxidation kinetics, to reduce external bias, and to improve the energy harvesting efficiency of photoelectrochemical (PEC) water oxidation. Here, the surface of porous BiVO 4 photoanodes was modified by the deposition of undoped and Ni-doped CoO x via nitrogen flow assisted electrostatic spray pyrolysis. This newly developed atmospheric pressure deposition technique allows for surface coverage throughout the porous structure with thickness and composition control. PEC testing of modified BiVO 4 photoanodes shows that after deposition of an undoped CoO x surface layer, the onset potential shifts negatively by ca. 420 mV and the photocurrent density reaches 2.01 mA cm –2 at 1.23 vs V RHE under AM 1.5G illumination. Modification with Ni-doped CoO x produces even more effective OER catalysis and yields a photocurrent density of 2.62 mA cm –2 at 1.23 V RHE under AM 1.5G illumination. Furthermore, the valence band X-ray photoelectron spectroscopy and synchrotron-based X-ray absorption spectroscopy results show the Ni doping reduces the Fermi level of the CoO x layer; the increased surface band bending produced by this effect is partially responsible for the superior PEC performance.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Xi'an Jiaotong Univ., Shaanxi (China)
  2. Univ. of California, San Diego, La Jolla, CA (United States)
  3. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  4. Xi'an Jiaotong Univ., Shaanxi (China)
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-76SF00515; SC0004993; 51302211; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 120; Journal Issue: 41; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1350543
Alternate Identifier(s):
OSTI ID: 1379585

Liu, Ya, Guo, Youhong, Schelhas, Laura T., Li, Mingtao, and Ager, Joel W.. Undoped and Ni-doped CoOx surface modification of porous BiVO4 photoelectrodes for water oxidation. United States: N. p., Web. doi:10.1021/acs.jpcc.6b08654.
Liu, Ya, Guo, Youhong, Schelhas, Laura T., Li, Mingtao, & Ager, Joel W.. Undoped and Ni-doped CoOx surface modification of porous BiVO4 photoelectrodes for water oxidation. United States. doi:10.1021/acs.jpcc.6b08654.
Liu, Ya, Guo, Youhong, Schelhas, Laura T., Li, Mingtao, and Ager, Joel W.. 2016. "Undoped and Ni-doped CoOx surface modification of porous BiVO4 photoelectrodes for water oxidation". United States. doi:10.1021/acs.jpcc.6b08654. https://www.osti.gov/servlets/purl/1350543.
@article{osti_1350543,
title = {Undoped and Ni-doped CoOx surface modification of porous BiVO4 photoelectrodes for water oxidation},
author = {Liu, Ya and Guo, Youhong and Schelhas, Laura T. and Li, Mingtao and Ager, Joel W.},
abstractNote = {Surface modification of photoanodes with oxygen evolution reaction (OER) catalysts is an effective approach to enhance water oxidation kinetics, to reduce external bias, and to improve the energy harvesting efficiency of photoelectrochemical (PEC) water oxidation. Here, the surface of porous BiVO4 photoanodes was modified by the deposition of undoped and Ni-doped CoOx via nitrogen flow assisted electrostatic spray pyrolysis. This newly developed atmospheric pressure deposition technique allows for surface coverage throughout the porous structure with thickness and composition control. PEC testing of modified BiVO4 photoanodes shows that after deposition of an undoped CoOx surface layer, the onset potential shifts negatively by ca. 420 mV and the photocurrent density reaches 2.01 mA cm–2 at 1.23 vs VRHE under AM 1.5G illumination. Modification with Ni-doped CoOx produces even more effective OER catalysis and yields a photocurrent density of 2.62 mA cm–2 at 1.23 VRHE under AM 1.5G illumination. Furthermore, the valence band X-ray photoelectron spectroscopy and synchrotron-based X-ray absorption spectroscopy results show the Ni doping reduces the Fermi level of the CoOx layer; the increased surface band bending produced by this effect is partially responsible for the superior PEC performance.},
doi = {10.1021/acs.jpcc.6b08654},
journal = {Journal of Physical Chemistry. C},
number = 41,
volume = 120,
place = {United States},
year = {2016},
month = {9}
}