期刊
NANO ENERGY
卷 28, 期 -, 页码 250-260出版社
ELSEVIER
DOI: 10.1016/j.nanoen.2016.08.046
关键词
Active sites; Heterojunction; Type II band structure; BiVO4; WO3; Pulsed electrodeposition
类别
资金
- Center for Integrated Smart Sensors - Ministry of Science, ICT & Future Planning as the Global Frontier Project
- Outstanding Young Researcher Program through National Research Foundation of Korea [2016924125]
- International Energy Joint R&D Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP)
- Ministry of Trade, Industry & Energy, Republic of Korea [20168510011350]
- Global Ph.D. Fellowship Program through National Research Foundation of Korea - Ministry of Education [2015H1A2A1034356]
- National Research Foundation of Korea [2015H1A2A1034356] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
Bismuth vanadate (BiVO4) has become a hot topic for solar hydrogen generation by water oxidation due to its appropriate band edges, and narrow band gap. However, the actual conversion efficiency achieved with BiVO4-based photoanodes is considerably less than the theoretical values because of drawbacks such as poor electron transportation and slow kinetics of oxygen evolution. In these respects, formation of nanostructured heterojunctions is considered to have a marked effect in terms of improving the photoactivities of BiVO4 photoanodes since it is possible to enhance the charge transfer at the interface and increase light absorption significantly. Herein, we report the synthesis and photoelectrochemical (PEC) properties of various BiVO4-based heterojunction anodes based on stoichiometric BiVO4 by pulsed electrodeposition. We show that WO3 is the optimum bottom layer for a type II band system with BiVO4 among various metal oxides. It is revealed that the photocurrent density of bare WO3 nanorods can be changed drastically by controlling the porosity and aspect ratio and thus BiVO4/WO3 heterojunction anodes show as similar tendency to bare WO3 nanorods. Under the optimum conditions, a BiVO4/WO3 heterojunction anode can lead to a high photocurrent density of 4.55 mA/cm(2) and an incident photon to current conversion efficiency of 80% at 1.23 V versus a reversible hydrogen electrode without additional catalyst. Cross-sectional transmission electron microscopy shows that dot-like BiVO4 is well decorated on the entire surface of WO3 nanorods. This systematic study provides a viewpoint on the crucial role of the active area of the bottom layer for high-performance BiVO4-based type II heterojunction photoanodes, and the proposed concept is applicable to various photoelectrode systems. (C) 2016 Elsevier Ltd. All rights reserved.
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