title: WO₃ nanoflakes for enhanced photoelectrochemical conversion.
abstract: We developed a postgrowth modification method of two-dimensional WO3 nanoflakes by a simultaneous solution etching and reducing process in a weakly acidic condition. The obtained dual etched and reduced WO3 nanoflakes have a much rougher surface, in which oxygen vacancies are created during the simultaneous etching/reducing process for optimized photoelectrochemical performance. The obtained photoanodes show an enhanced photocurrent density of ∼1.10 mA/cm(2) at 1.0 V vs Ag/AgCl (∼1.23 V vs reversible hydrogen electrode), compared to 0.62 mA/cm(2) of pristine WO3 nanoflakes. The electrochemical impedance spectroscopy measurement and the density functional theory calculation demonstrate that this improved performance of dual etched and reduced WO3 nanoflakes is attributed to the increase of charge carrier density as a result of the synergetic effect of etching and reducing.
authors.affiliation: Laboratory of Advanced Materials, Department of Chemistry and ‡Key Laboratory of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University , Shanghai, 200433, China.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Li
authors.forename: Peimei
authors.initials: P
authors.lastname: Da
authors.forename: Yueyu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yongcheng
authors.initials: Y
authors.lastname: Wang
authors.forename: Xuan
authors.initials: X
authors.lastname: Lin
authors.forename: Xingao
authors.initials: X
authors.lastname: Gong
authors.forename: Gengfeng
authors.initials: G
authors.lastname: Zheng
keywords: WO3; etching; nanoflakes; oxygen vacancy; photoelectrochemical; reducing