title: Enhanced Charge Separation through ALD-Modified Fe2 O3 /Fe2 TiO5 Nanorod Heterojunction for Photoelectrochemical Water Oxidation.
abstract: Hematite suffers from poor charge transport and separation properties for solar water splitting. This paper describes the design and fabrication of a 3D Fe2 O3 /Fe2 TiO5 heterojunction photoanode with improved charge separation, via a facile hydrothermal method followed by atomic layer deposition and air annealing. A highly crystallized Fe2 TiO5 phase forms with a distinct interface with the underlying Fe2 O3 core, where a 4 nm Fe2 TiO5 overlayer leads to the best photoelectrochemical performance. The favorable band offset between Fe2 O3 and Fe2 TiO5 establishes a type-II heterojunction at the Fe2 O3 /Fe2 TiO5 interface, which drives electron-hole separation effectively. The Fe2 O3 /Fe2 TiO5 composite electrode exhibits a dramatically improved photocurrent of 1.63 mA cm(-2) at 1.23 V versus reversible hydrogen electrode (RHE) under simulated 1 sun illumination (100 mW cm(-2) ), which is 3.5 times that of the bare Fe2 O3 electrode. Decorating the Fe2 O3 /Fe2 TiO5 heterojunction photoanode with earth-abundant FeNiOx cocatalyst further expedites surface reaction kinetics, leading to an onset potential of 0.8 V versus RHE with a photocurrent of 2.7 mA cm(-2) at 1.23 V and 4.6 mA cm(-2) at 1.6 V versus RHE. This sandwich photoanode shows an excellent stability for 5 h and achieves an overall Faradaic efficiency of 95% for O2 generation. This is the best performance ever reported for Fe2 O3 /Fe2 TiO5 photoanodes.
authors.affiliation: Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, P. R. China.|Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, P. R. China.
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Li
authors.affiliation: Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, P. R. China.|Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, P. R. China.
authors.forename: Tuo
authors.initials: T
authors.lastname: Wang
authors.affiliation: Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, P. R. China.|Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, P. R. China.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Luo
authors.affiliation: Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, P. R. China.|Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, P. R. China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Liu
authors.affiliation: Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, P. R. China.|Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, P. R. China.
authors.forename: Jinlong
authors.initials: J
authors.lastname: Gong
keywords: hematite (Fe2O3); heterojunctions; iron titanate (Fe2TiO5); photoanodes; water oxidation