Remarkable improvements in the performance and stability of Si photoanodes adopting nanocrystalline NiOx electrocatalyst and stoichiometric SiO2 protection
- Title
- Remarkable improvements in the performance and stability of Si photoanodes adopting nanocrystalline NiOx electrocatalyst and stoichiometric SiO2 protection
- Author
- 이정호
- Keywords
- Water splitting; Photoelectrochemical cells; Si photoanode; NiOx electrocatalyst; Long-term stability
- Issue Date
- 2019-11
- Publisher
- ELSEVIER SCIENCE BV
- Citation
- APPLIED SURFACE SCIENCE, v. 493, Page. 1150-1158
- Abstract
- Silicon photoanodes have been studied intensively for efficient photoelectrochemical (PEC)-mediated catalysis of the oxygen evolution reaction, but their performance and stability still need to be improved before they can be applied practically. Here, we demonstrate that the porous, nanocrystalline NiOx electrocatalyst integrated with a thermally-grown SiO2 protection layer results in unexpectedly high PEC performances as well as long-term stability in Si photoanodes. The porous structure of NiO(x )and its large active area in contact to the electrolyte improves electrocatalytic activity and greatly reduces the kinetic overpotential required for charge transfer. In addition, the redox-active surface contributed by nanocrystalline nature of NiOx results in the accumulation of charges during the PEC reaction, predominantly affecting the interface energetics of NiOx/n-Si junctions. This feature enables a high open circuit potential of similar to 0.6 V even without p-n junctions. Stoichiometric SiO2 affords strong electrochemical corrosion resistance during the PEC water oxidation in 1 M KOH electrolyte, in contrast to the wet chemical-grown, nonstoichiometric SiOx. The porous and nanocrystalline NiOx and stoichiometric SiO2 incorporated in the n-Si photoanode ensures continuous operation for 100 h at high performance. These results can help inform a new way to design a high performance Si photoanodes with long-term stability.
- URI
- https://www.sciencedirect.com/science/article/pii/S0169433219321646https://repository.hanyang.ac.kr/handle/20.500.11754/121940
- ISSN
- 0169-4332; 1873-5584
- DOI
- 10.1016/j.apsusc.2019.07.128
- Appears in Collections:
- COLLEGE OF ENGINEERING SCIENCES[E](공학대학) > MATERIALS SCIENCE AND CHEMICAL ENGINEERING(재료화학공학과) > Articles
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