Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University , Suzhou 215123, China.
ACS Appl Mater Interfaces. 2016 Apr 13;8(14):9211-7. doi: 10.1021/acsami.6b03176. Epub 2016 Apr 1.
Over recent years, tremendous efforts have been invested in the search and development of active and durable semiconductor materials for photoelectrochemical (PEC) water splitting, particularly for photoanodes operating under a highly oxidizing environment. CuWO4 is an emerging candidate with suitable band gap and high chemical stability. Nevertheless, its overall solar-to-electricity remains low because of the inefficient charge separation process. In this work, we demonstrate that this problem can be partly alleviated through designing three-dimensional hierarchical nanostructures. CuWO4 nanoflake arrays on conducting glass are prepared from the chemical conversion of WO3 templates. Resulting electrode materials possess large surface areas, abundant porosity and small thickness. Under illumination, our CuWO4 nanoflake array photoanodes exhibit an anodic current density of ∼0.4 mA/cm(2) at the thermodynamic potential of water splitting in pH 9.5 potassium borate buffer--the largest value among all available CuWO4-based photoanodes. In addition, we demonstrate that their performance can be further boosted to >2 mA/cm(2) by coupling with a solution-cast BiVO4 film in a heterojunction configuration. Our study unveils the great potential of nanostructured CuWO4 as the photoanode material for PEC water oxidation.
近年来，人们在寻找和开发用于光电化学（PEC）水分解的活性和耐用半导体材料方面投入了巨大的努力，特别是对于在强氧化环境下工作的光阳极。CuWO4 是一种新兴的候选材料，具有合适的带隙和高化学稳定性。然而，由于电荷分离过程效率低下，其整体太阳能到电能的转换效率仍然较低。在这项工作中，我们证明通过设计三维分层纳米结构可以部分缓解这个问题。我们通过化学转化 WO3 模板制备了在导电玻璃上的 CuWO4 纳米片阵列。所得电极材料具有大的表面积、丰富的孔隙率和小的厚度。在光照下，我们的 CuWO4 纳米片阵列光阳极在 pH9.5 硼酸钾缓冲溶液中的热力学水分解电势下表现出约 0.4 mA/cm2 的阳极电流密度，这是所有可用的基于 CuWO4 的光阳极中最大的值。此外，我们证明通过在异质结结构中与溶液浇铸的 BiVO4 薄膜耦合，其性能可以进一步提高到>2 mA/cm2。我们的研究揭示了纳米结构 CuWO4 作为 PEC 水氧化光阳极材料的巨大潜力。
