Fe2PO5‐Encapsulated Reverse Energetic ZnO/Fe2O3 Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water. Issue 13 (1st June 2017)

• Record Type: Journal Article
• Authors: Qin, Dong‐Dong; He, Cai‐Hua; Li, Yang; Trammel, Antonio C.; Gu, Jing; Chen, Jing; Yan, Yong; Shan, Duo‐Liang; Wang, Qiu‐Hong; Quan, Jing‐Jing; Tao, Chun‐Lan; Lu, Xiao‐Quan
• Is Part Of: ChemSusChem. Volume 10:Issue 13(2017)
• Page Start: 2796
• Page End: 2804
• Publication Date: 2017-06-01
• Subjects: charge separation -- heterojunction -- overlayer -- photoelectrochemistry -- surface state; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201700501
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: Zinc oxide is regarded as a promising candidate for application in photoelectrochemical water oxidation due to its higher electron mobility. However, its instability under alkaline conditions limits its application in a practical setting. Herein, we demonstrate an easily achieved wet‐chemical route to chemically stabilize ZnO nanowires (NWs) by protecting them with a thin layer Fe2 O3 shell. This shell, in which the thickness can be tuned by varying reaction times, forms an intact interface with ZnO NWs, thus protecting ZnO from corrosion in a basic solution. The reverse energetic heterojunction nanowires are subsequently activated by introducing an amorphous iron phosphate, which substantially suppressed surface recombination as a passivation layer and improved photoelectrochemical performance as a potential catalyst. Compared with pure ZnO NWs (0.4 mA cm −2 ), a maximal photocurrent of 1.0 mA cm −2 is achieved with ZnO/Fe2 O3 core–shell NWs and 2.3 mA cm −2 was achieved for the PH3 ‐treated NWs at 1.23 V versus RHE. The PH3 low‐temperature treatment creates a dual function, passivation and catalyst layer (Fe2 PO5 ), examined by X‐ray photoelectron spectroscopy, TEM, photoelectrochemical characterization, and impedance measurements. Such a nano‐composition design offers great promise to improve the overall performance of the photoanode material. Abstract : A passive catalyst? A Fe2 O3 shell was grown onto a ZnO core to protect the surface from corrosion and increase the charge‐separation efficiency. PH3 treatment onto the core–shell nanowire creates a Fe2 PO5 with dual functionality: a catalyst and passivating overlayer.