Fabrication of CdS/P2MoxW18-x nanospheres with type II heterostructure for photocatalytic reduction of hexavalent chromium. (December 2020)

• Record Type: Journal Article
• Authors: Liu, Caixia; Fang, Wencheng; Song, Yuting; Li, Fengyan; Sun, Zhixia; Xu, Lin
• Is Part Of: Materials science in semiconductor processing. Volume 120(2020)
• Publication Date: 2020-12
• Subjects: Polyoxometalate -- CdS -- Semiconductor -- Visible-light photocatalyst -- Cr(VI); Semiconductors -- Periodicals; Integrated circuits -- Materials -- Periodicals; Semiconducteurs -- Périodiques; Circuits intégrés -- Matériaux -- Périodiques; Electronic journals; 621.38152
• DOI: 10.1016/j.mssp.2020.105276
• Languages: English
• ISSNs: 1369-8001

Abstract

Abstract: A serial of CdS/POM (POM denotes polyoxometalate: P2 Mox W18-x, x = 3, 9, 15) nanospheres were fabricated through electrostatic self-assembly method. For the first time, the semiconductor properties of the three polyoxometalates were investigated to direct the rational design of the type-II heterojunction photocatalysts. The morphology and semiconducting properties of the as-prepared materials were characterized by using X-ray powder diffraction, scanning electron microscopy, UV–vis diffuse reflectance spectra, Mott-Schottky plots, surface photovoltage spectroscopy and time-resolved photocurrent curves. The band gap of P2 Mo3 W15, P2 Mo9 W9 and P2 Mo15 W3 is taken respectively to be 2.34 eV, 2.26 eV and 2.15 eV. The average diameters of CdS and CdS/P2 Mox W18-x (X = 3, 9, 15) nanospheres are all around 80–100 nm, and CdS/P2 Mox W18-x (X = 3, 9, 15) nanospheres have better photoelectric performance than pure CdS. The formation of type II heterostructure between CdS and P2 Mox W18-x could promote the separation and transfer of photoinduced electron-hole pairs, so the photocatalytic activities of CdS/POM nanospheres for Cr(VI) reduction were improved significantly. Among them, the CdS/P2 Mo15 W3 photocatalyst exhibited the highest photocatalytic yield of 64% for the Cr(VI) removal. Our study provides new insight into developing novel CdS/P2 Mox W18-x nanocomposite photocatalysts for environmental applications. Highlights: Nanocomposite photocatalysts of CdS/polyoxometalates were fabricated. Semiconductor properties of the mixed Mo/W polyoxometalates were investigated. Photocatalytic removal of Cr(VI) was improved by CdS/polyoxometalates catalyst. Photocatalytic yield of 64% was achieved for the removal of Cr(VI).