title: Photoelectrochemical Properties and Behavior of α-SnWO4Photoanodes Synthesized by Hydrothermal Conversion of WO3Films.
abstract: Metal oxides with moderate band gaps are desired for efficient production of hydrogen from sunlight and water via photoelectrochemical (PEC) water splitting. Here, we report an α-SnWO4photoanode synthesized by hydrothermal conversion of WO3films that achieves photon to current conversion at wavelengths up to 700 nm (1.78 eV). This photoanode is promising for overall PEC water-splitting because the flat-band potential and voltage of photocurrent onset are more negative than the potential of hydrogen evolution. Furthermore, the photoanode utilizes a large portion of the solar spectrum. However, the photocurrent density reaches only a small fraction of that which is theoretically possible. Density functional theory based thermodynamic and electronic structure calculations were performed to elucidate the nature and impact of defects in α-SnWO4prepared by this synthetic route, from which hole localization at Sn-at-W antisite defects was determined to be a likely cause for the poor photocurrent. Measurements further showed that the photocurrent decreases over time due to surface oxidation, which was suppressed by improving the kinetics of hole transfer at the semiconductor/electrolyte interface. Alternative synthetic methods and the addition of protective coatings and/or oxygen evolution catalysts are suggested to improve the PEC performance and stability of this promising α-SnWO4material.
authors.affiliation: Department of Chemistry and Biochemistry, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States.|Department of Chemical Engineering, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States.
authors.forename: Zhehao
authors.identifier: http://orcid.org/0000-0002-2510-8769
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Physics, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors.forename: Pranab
authors.initials: P
authors.lastname: Sarker
authors.affiliation: Materials Science and Engineering Graduate Program, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States.
authors.forename: Chenqi
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Materials Science and Engineering Graduate Program, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States.
authors.forename: Lite
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Department of Chemistry and Biochemistry, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States.
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Grimm
authors.affiliation: Department of Physics, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors.forename: Muhammad N
authors.initials: MN
authors.lastname: Huda
authors.affiliation: Materials Science and Engineering Graduate Program, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States.|Department of Mechanical Engineering, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States.
authors.forename: Pratap M
authors.identifier: http://orcid.org/0000-0003-1324-498X
authors.initials: PM
authors.lastname: Rao
keywords: BiVO4; SnWO4; photocatalysis; photoelectrochemical; tin tungstate; water splitting