A Rational Design of Heterojunction Photocatalyst Cd S Interfacing with One Cycle of ALD Oxide
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2016年第6期
论文作者：Mengyin Liu Xinjian Xie Lei Chen Xuewei Wang Yahui Cheng Feng Lu Wei-Hua Wang Jing Yang Xiwen Du Junda Zhu Haitao Liu Hong Dong Weichao Wang Hui Liu
文章页码：489 - 495
摘 要：Photo-corrosion is one of the major obstacles for Cd S application in wet chemical fields, and atomic layer deposition（ALD） has been proposed as an effective way to suppress the corrosion. Here, prior to ALD coating, Cd S, one facilely corrosive photocatalyst, was synthesized via hydrothermal synthesis to access the fundamental corrosion mechanism and the according corrosive sites. X-ray photoelectron spectroscopy（XPS） and X-ray diffraction（XRD） demonstrated that the failure of catalytic decomposition of methylene blue originated from the formation of soluble Cd SO4 by oxidizing S2- of as-prepared Cd S. High resolution transmission electron microscopy（HRTEM） further identified the active sites in the V-shaped regions of Cd S nanoparticles, confirmed by the simulated electric field distribution. To rationally coat oxides on Cd S, the right candidates and their thicknesses have been considered by our tunneling model with transfer matrix method based on quantum mechanism, upon which the thickness of protective layer should be less than 0.5 nm to maintain a high tunneling probability, and thus one cycle of ALD Ti O2 or Al2O3 was proposed to passivate the Cd S powder to balance the carrier transportation and corrosion suppression. Based on HRTEM results, we found that the active V-shaped region was covered by ALD oxides（TiO2 or Al2O3）. For each case, no soluble Cd SO4 has been found before and after photocatalytic reactions based XPS measurements. Importantly, we noticed that with the passivation of one cycle of ALD, the catalyst’s lifetime was elongated up to >14 times higher than that of the as-prepared Cd S.
Mengyin Liu1，Xinjian Xie2，Lei Chen1，Xuewei Wang3，Yahui Cheng1，Feng Lu1，Wei-Hua Wang1，Jing Yang4，Xiwen Du4，Junda Zhu5，Haitao Liu5，Hong Dong1，Weichao Wang1,2，Hui Liu1
1. Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin,Nankai University2. School of Material Science and Engineering,Hebei University of Technology3. Institute of Material Physics,Key Laboratory of Display Materials and Photoelectric Devices,Tianjin University of Technology4. Tianjin Key Laboratory of Composite and Functional Materials and School of Materials Science and Engineering,Tianjin University5. Key Laboratory of Optical Information Science and Technology,Ministry of Education,Institute of Modern Optics,Nankai University
摘 要：Photo-corrosion is one of the major obstacles for Cd S application in wet chemical fields, and atomic layer deposition（ALD） has been proposed as an effective way to suppress the corrosion. Here, prior to ALD coating, Cd S, one facilely corrosive photocatalyst, was synthesized via hydrothermal synthesis to access the fundamental corrosion mechanism and the according corrosive sites. X-ray photoelectron spectroscopy（XPS） and X-ray diffraction（XRD） demonstrated that the failure of catalytic decomposition of methylene blue originated from the formation of soluble Cd SO4 by oxidizing S2- of as-prepared Cd S. High resolution transmission electron microscopy（HRTEM） further identified the active sites in the V-shaped regions of Cd S nanoparticles, confirmed by the simulated electric field distribution. To rationally coat oxides on Cd S, the right candidates and their thicknesses have been considered by our tunneling model with transfer matrix method based on quantum mechanism, upon which the thickness of protective layer should be less than 0.5 nm to maintain a high tunneling probability, and thus one cycle of ALD Ti O2 or Al2O3 was proposed to passivate the Cd S powder to balance the carrier transportation and corrosion suppression. Based on HRTEM results, we found that the active V-shaped region was covered by ALD oxides（TiO2 or Al2O3）. For each case, no soluble Cd SO4 has been found before and after photocatalytic reactions based XPS measurements. Importantly, we noticed that with the passivation of one cycle of ALD, the catalyst’s lifetime was elongated up to >14 times higher than that of the as-prepared Cd S.
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