The band edge positions of semiconductors determine functionality in solar water splitting. While ligand exchange is known to enable modification of the band structure, its crucial role in water splitting efficiency is not yet fully understood. Here, ligand-engineered manganese oxide cocatalyst nanoparticles (MnO NPs) on bismuth vanadate (BiVO4) anodes are first demonstrated, and a remarkably enhanced photocurrent density of 6.25 mA cm−2 is achieved. It is close to 85% of the theoretical photocurrent density (≈7.5 mA cm−2) of BiVO4. Improved photoactivity is closely related to the substantial shifts in band edge energies that originate from both the induced dipole at the ligand/MnO interface and the intrinsic dipole of the ligand. Combined spectroscopic analysis and electrochemical study reveal the clear relationship between the surface modification and the band edge positions for water oxidation. The proposed concept has considerable potential to explore new, efficient solar water splitting systems.
Bibliographical noteFunding Information:
M.G.L. and K.J. contributed equally to this work. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (Grant No. 2017R1A2B3009135). M.G.L. acknowledges the Global PhD Fellowship Program through the National Research Foundation of Korea funded by the Ministry of Education (Grant No. 2015H1A2A1034356).
© 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
- band structure
- ligand engineering
- oxygen evolution catalysts
- water splitting
ASJC Scopus subject areas
- Medicine (miscellaneous)
- General Chemical Engineering
- Biochemistry, Genetics and Molecular Biology (miscellaneous)
- General Materials Science
- General Engineering
- General Physics and Astronomy