Hierarchical TiO2@In2O3 heteroarchitecture photoanodes: Mechanistic study on interfacial charge carrier dynamics through water splitting and organic decomposition

• Published in: Applied surface science 2019-06, Vol.480, p.1-12
• Main Authors: An, Gil Woo, Mahadik, Mahadeo A., Piao, Guangxia, Chae, Weon-Sik, Park, Hyunwoong, Cho, Min, Chung, Hee-Suk, Jang, Jum Suk
• Format: Article
• Language: English
• Subjects: BPA degradation; Charge transfer mechanism; Photoelectrochemical hydrogen generation; TiO2@In2O3 heteroarchitecture photoelectrodes
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.02.196

In this study, we have synthesized hierarchical TiO2@In2O3 heteroarchitecture photoanodes via a hydrothermal method and studied their interfacial charge carrier dynamics through water splitting and organic decomposition. Photoelectrochemical measurements show that the IN-0.4 exhibits an obvious enhancement in photocurrent density compared to the pristine TiO2. Electrochemical impendence spectroscopy (EIS) and Time-resolved photoluminescence (PL) have been employed to study the charge recombination in TiO2@In2O3 nanostructure. The surface passivation of TiO2 nanorods (NRs) with In2O3 nanostructures helps to the suppression of the surface defects. The surface-passivated photoanode (IN-0.4) has demonstrated the improved hydrogen generation activity (125 μmol∙h−1) of TiO2 nanorods (NRs) with In2O3 nanostructures during water splitting and organic decomposition. The probable causes of the enhancement in hydrogen evolution could be due to (i) enhanced photogenerated electron transport (ii) increased active surface area with In2O3 and/or (iii) catalytic activity of In2O3. Moreover, the photoelectrocatalytic activities of IN-0.4 were slight affect during degradation of Bisphenol A and methyl orange dye, which might be due to the lower hole mobility in TiO2@In2O3 heteroarchitecture photoelectrodes. These sightings and proposed schematic model can help to understand the charge transfer dynamics in hierarchical TiO2@In2O3 heteroarchitecture photoelectrodes as well as designing multifaceted photoelectrodes for solar energy conversion. A detailed mechanism of the interfacial charge carrier dynamics in hierarchical TiO2@In2O3 photoelectrodes during photoelectrochemical hydrogen generation and BPA degradation performances is described. [Display omitted] •TiO2@In2O3 heteroarchitecture photoanode was prepared by facile hydrothermal method.•TiO2@In2O3 heteroarchitecture photoanode shows excellent solar hydrogen generation.•125 μmol∙h−1 hydrogen generation and 94% MO degradation was achieved.•In-depth interfacial electron transfer mechanism was proposed.•This work contributes a deep insight to the interfacial charge carrier dynamics during photoelectrochemical process.