title: A Facile Surface Passivation of Hematite Photoanodes with Iron Titanate Cocatalyst for Enhanced Water Splitting.
abstract: The surface modification of semiconductor photoelectrodes with passivation overlayers has attracted great attention as an effective strategy to improve the charge separation and charge transfer processes across the semiconductor-electrolyte interface. In this work, a thin Fe2 TiO5 layer was decorated on nanostructured hematite nanoflake and nanocoral photoanodes (by thermal oxidation of iron foils) by a facile water-based solution method. Photoelectrochemical measurements show that the Fe2 O3 /Fe2 TiO5 heterostructure exhibits an obvious enhancement in photoelectrochemical water oxidation performance compared to the pristine hematite. For example, at 1.23 V versus the reversible hydrogen electrode (VRHE ) in 1 m KOH under AM 1.5 G (100 mW cm(-2) ) illumination, a 4-8× increase in the water oxidation photocurrent is achieved for Fe2 O3 /Fe2 TiO5 , and a considerable cathodic shift of the onset potential up to 0.53-0.62 VRHE is obtained. Moreover, the performance of the Fe2 O3 /Fe2 TiO5 heterostructure can be further improved by decoration with a SnOx layer. The enhancement in photocurrent can be attributed to the synergistic effect of Fe2 TiO5 /SnOx overlayers passivating surface states, and thus reducing surface electron-hole recombination.
authors.affiliation: Department of Materials Science and Engineering, WW4-LKO, University of Erlangen-Nuremburg, Martensstrasse 7, 91058, Erlangen, Germany.|State Key Laboratory for Oxo Synthesis and Selective Oxidation National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Materials Science and Engineering, WW4-LKO, University of Erlangen-Nuremburg, Martensstrasse 7, 91058, Erlangen, Germany.
authors.forename: Nhat Truong
authors.initials: NT
authors.lastname: Nguyen
authors.affiliation: Department of Materials Science and Engineering, WW4-LKO, University of Erlangen-Nuremburg, Martensstrasse 7, 91058, Erlangen, Germany. schmuki@ww.uni-erlangen.de.|Department of Chemistry, King Abdulaziz University, Jeddah, Saudi Arabia. schmuki@ww.uni-erlangen.de.
authors.forename: Patrik
authors.initials: P
authors.lastname: Schmuki
mesh_terms: D011211:Electric Power Supplies; D004563:Electrochemistry; D004566:Electrodes; D005290:Ferric Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D012993:Solar Energy; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D014867:Water; C000499:ferric oxide; D014025:Titanium
keywords: hematite; iron titanate; passivation layer; tin oxides; water splitting