Evaluation of sputtered nickel oxide, cobalt oxide and nickel–cobalt oxide on n-type silicon photoanodes for solar-driven O₂(g) evolution from water
Abstract
Thin films of nickel oxide (NiO_x), cobalt oxide (CoO_x) and nickel–cobalt oxide (NiCoO_x) were sputtered onto n-Si(111) surfaces to produce a series of integrated, protected Si photoanodes that did not require deposition of a separate heterogeneous electrocatalyst for water oxidation. The p-type transparent conductive oxides (p-TCOs) acted as multi-functional transparent, antireflective, electrically conductive, chemically stable coatings that also were active electrocatalysts for the oxidation of water to O₂(g). Relative to the formal potential for water oxidation to O₂, E^(o′)(O₂/H₂O), under simulated Air Mass (AM)1.5 illumination the p-TCO-coated n-Si(111) photoanodes produced mutually similar open-circuit potentials of −270 ± 20 mV, but different photocurrent densities at E^(o′)(O₂/H₂O), of 28 ± 0.3 mA cm⁻² for NiO_x, 18 ± 0.3 mA cm⁻² for CoO_x and 24 ± 0.5 mA cm⁻² for NiCoO_x. The p-TCOs all provided protection from oxide growth for extended time periods, and produced stable photocurrent densities from n-Si in 1.0 M KOH(aq) (ACS grade) under potential control at E^(o′)(O₂/H₂O) for >400 h of continuous operation under 100 mW cm−2 of simulated AM1.5 illumination.
Additional Information
© 2020 The Royal Society of Chemistry. Received 8th April 2020; Accepted 26th June 2020; First published 30 Jun 2020. This work was supported through the Office of Science of the U.S. Department of Energy (DOE) under award DE-SC0004993 to the Joint Center for Artificial Photosynthesis (JCAP), a DOE funded Energy Innovation Hub. UV-vis absorption and Atomic Force Microscope studies were performed at the Molecular Materials Resource Center (MMRC) in the Beckman Institute at the California Institute of Technology. Paul Kempler and Weilai Yu are thanked for assistance with editing the manuscript. There are no conflicts to declare.Attached Files
Supplemental Material - d0ta03725g1.pdf
Files
Name | Size | Download all |
---|---|---|
md5:fea4f186756351c7af61a487130f48e2
|
1.2 MB | Preview Download |
Additional details
- Eprint ID
- 104358
- Resolver ID
- CaltechAUTHORS:20200713-130247847
- Department of Energy (DOE)
- DE-SC0004993
- Created
-
2020-07-13Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field
- Caltech groups
- JCAP