3D Si/ITO/WO3 photoelectrode with a micropost array structure for photocatalysis enhancement

• Published in: Journal of micromechanics and microengineering Vol. 27; no. 11
• Main Authors: Zheng, Deyin, Jiang, Xiufen, Liu, Mengyin, Zhao, Xin, Wang, Weichao, Sun, Guangyi
• Format: Journal Article
• Language: English
• Published: IOP Publishing 20.10.2017
• Subjects: deep reactive ion etching (DRIE); high-aspect-ratio (HAR); photocatalysis; photoelectrode; tungsten trioxide (WO
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/1361-6439/aa839b

In this paper, a three-dimensional (3D) tandem Si/ITO/WO3 photoelectrode system with a high-aspect-ratio (HAR) micropost array structure based on a 'Z-scheme' is designed to enhance photocatalytic performance. To produce such a photoelectrode system, microposts were first fabricated on a Si substrate by deep reactive ion etching (DRIE), followed by deposition of an indium tin oxide (ITO) layer and tungsten trioxide (WO3) layer on microposts. The photocatalytic performance was verified by the degradation of methylene blue (MB, C16H18ClN3S) under visible light conditions. In the photocatalytic test, photoelectrode samples of a 0.5 cm2 footprint were used to degrade 15 ml MB (10 mg l−1). Experimental results indicate that the 3D micropost WO3/ITO/Si structure has a higher efficiency compared with the 2D planar WO3/ITO/Si structure. A decrease of 83.6% in MB concentration within 30 min is observed in the preliminary degradation test. The HAR photoelectrode configuration can dramatically increase the surface-to-volume ratio, not only increasing the total incident light absorption efficiency, but also facilitating the oxidation-reduction reaction in the semiconductor-liquid interface.