Abstract
Synthesizing low-cost electrocatalysts using earth-abundant metals is the foremost task in water-splitting techniques. This study mainly discusses the enhancing effects of cobalt oxide (CoOx) on the photocurrent of gallium nitride (GaN) photoelectrodes in a photoelectrochemical (PEC) system for hydrogen generation. The CoOx nanofilm is formed on a GaN epitaxial layer through the thermal evaporation and post-deposition thermal annealing of cobalt metal. The X-ray photoemission spectroscopy spectra confirm that the exposed metal ions in the as-deposited films are Co3+ and Co2+. The chemical composition of the annealed CoOx films is more biased toward Co3+ than that of as-deposited films. This finding indicates that it is suitable for water oxidation during a PEC reaction for water splitting because the films may contain more CoOOH. Besides, a CoOx/n-GaN heterostructure can form a built-in electric field at the interface between n-GaN and CoOx and hence increase the charge separation efficiency. The photocurrent of photoelectrodes made of GaN and decorated with the CoOx nanofilm significantly improves compared with those of bare n-GaN photoelectrodes.
Original language | English |
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Pages (from-to) | 25196-25201 |
Number of pages | 6 |
Journal | Journal of Physical Chemistry C |
Volume | 124 |
Issue number | 46 |
DOIs | |
Publication status | Published - 2020 Nov 19 |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Energy(all)
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films