Ferroelectric Polarization-Enhanced Photoelectrochemical Water Splitting in TiO2–BaTiO3 Core–Shell Nanowire Photoanodes
- 23 October 2015
- journal article
- research article
- Published by American Chemical Society (ACS) in Nano Letters
- Vol. 15 (11), 7574-7580
- https://doi.org/10.1021/acs.nanolett.5b03988
Abstract
The performances of heterojunction-based electronic devices are extremely sensitive to the interfacial electronic band structure. Here we report a largely enhanced performance of photoelectrochemical (PEC) photoanodes by ferroelectric polarization-endowed band engineering on the basis of TiO2/BaTiO3 core/shell nanowires (NWs). Through a one-step hydrothermal process, a uniform, epitaxial, and spontaneously poled barium titanate (BTO) layer was created on single crystalline TiO2 NWs. Compared to pristine TiO2 NWs, the 5 nm BTO-coated TiO2 NWs achieved 67% photocurrent density enhancement. By numerically calculating the potential distribution across the TiO2/BTO/electrolyte heterojunction and systematically investigating the light absorption, charge injection and separation properties of TiO2 and TiO2/BTO NWs, the PEC performance gain was proved to be a result of the increased charge separation efficiency induced by the ferroelectric polarization of the BTO shell. The ferroelectric polarization could be switched by external electric field poling and yielded PEC performance gain or loss based on the direction of the polarization. This study evidence that the piezotronic effect (ferroelectric or piezoelectric potential-induced band structure engineering) holds great promises in improving the performance of PEC photoelectrodes in addition to chemistry and structure optimization.Keywords
Funding Information
- China Scholarship Council
- National Natural Science Foundation of China (51202139)
- Ministry of Education of the People's Republic of China (20123108120022)
- Air Force Office of Scientific Research (FA9550-13-1-0168)
- Division of Civil, Mechanical and Manufacturing Innovation (CMMI-1148919)
This publication has 36 references indexed in Scilit:
- Enabling unassisted solar water splitting by iron oxide and siliconNature Communications, 2015
- A silicon-based photocathode for water reduction with an epitaxial SrTiO3 protection layer and a nanostructured catalystNature Nanotechnology, 2014
- Amorphous TiO 2 coatings stabilize Si, GaAs, and GaP photoanodes for efficient water oxidationScience, 2014
- Nanoporous BiVO 4 Photoanodes with Dual-Layer Oxygen Evolution Catalysts for Solar Water SplittingScience, 2014
- Simultaneously Efficient Light Absorption and Charge Separation in WO3/BiVO4 Core/Shell Nanowire Photoanode for Photoelectrochemical Water OxidationNano Letters, 2014
- High-Performance Silicon Photoanodes Passivated with Ultrathin Nickel Films for Water OxidationScience, 2013
- Identifying champion nanostructures for solar water-splittingNature Materials, 2013
- Atomic layer-deposited tunnel oxide stabilizes silicon photoanodes for water oxidationNature Materials, 2011
- Solar Water Splitting CellsChemical Reviews, 2010
- A Monolithic Photovoltaic-Photoelectrochemical Device for Hydrogen Production via Water SplittingScience, 1998