TJU-NIMS International Collaboration laboratory, Key Lab of Advanced Ceramics and Machining Technology (Ministry of Education), Tianjin Key Lab of Composite and Functional Materials, School of Materials Science and Engineering , Tianjin University , 92 Weijin Road , Tianjin 300072 , China.
Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , 92 Weijin Road , Tianjin 300072 , China.
ACS Appl Mater Interfaces. 2019 Feb 13;11(6):5623-5631. doi: 10.1021/acsami.8b05477. Epub 2018 Jul 13.
Constructing semiconductor heterojunctions via surface/interface engineering is an effective way to enhance the charge carrier separation/transport ability and thus the photoelectrochemical (PEC) properties of a photoelectrode. Herein, we report a conformal BiVO-layer/WO-nanoplate-array heterojunction photoanode modified with cobalt phosphate (Co-Pi) as oxygen evolution cocatalyst (OEC) for significant enhancement in PEC performances. The BiVO/WO nanocomposite is fabricated by coating a thin conformal BiVO layer on the surface of presynthesized WO nanoplate arrays (NPAs) via stepwise spin-coating, and the decoration of Co-Pi OEC is realized by photoassisted electrodeposition method. The optimized Co-Pi@BiVO/WO heterojunction photoanode shows a maximum photocurrent of 1.8 mA/cm at 1.23 V vs RHE in a phosphate buffer electrolyte under an AM1.5G solar simulator, which is 5 and 12 times higher than those of bare WO and BiVO photoanode, respectively. Measurements of UV-vis absorption spectra, electrochemical impedance spectra (EIS) and photoluminescence (PL) spectra reveal that the enhanced PEC performances can be attributed to the increased charge carrier separation/transport benefited from the type II nature of BiVO/WO heterojunction and the promoted water oxidation kinetics and photostability owing to the decoration of Co-Pi cocatalyst.
通过表面/界面工程构建半导体异质结是提高光电化学（PEC）性能的有效方法，因为这样可以增强载流子的分离/输运能力。在此，我们报告了一种在磷酸钴（Co-Pi）作为析氧共催化剂（OEC）的条件下，对具有共形 BiVO 层/WO 纳米板阵列异质结光阳极进行修饰，从而显著提高了PEC 性能。BiVO/WO 纳米复合材料是通过分步旋涂法在预先合成的 WO 纳米板阵列（NPAs）表面涂覆一层薄的共形 BiVO 层制备而成，而 Co-Pi OEC 的修饰则是通过光电辅助电沉积法实现的。优化后的 Co-Pi@BiVO/WO 异质结光阳极在 AM1.5G 太阳模拟器下磷酸盐缓冲电解液中 1.23 V vs RHE 时的最大光电流为 1.8 mA/cm，分别是 bare WO 和 BiVO 光阳极的 5 倍和 12 倍。紫外-可见吸收光谱、电化学阻抗谱（EIS）和光致发光（PL）光谱的测量表明，增强的 PEC 性能可归因于载流子分离/输运的增加，这得益于 BiVO/WO 异质结的 II 型特性，以及由于 Co-Pi 共催化剂的修饰而促进的水氧化动力学和光稳定性。
