title: Improved photoelectrochemical water oxidation by the WO3/CuWO4 composite with a manganese phosphate electrocatalyst.
abstract: We describe a composite of the n-type semiconductors for the photoelectrochemical oxygen evolution reaction (OER). A simple drop-casting technique of mixed precursors and a one-step annealing process were used in the synthesis of the WO3/CuWO4 composite. The composite showed improved photocurrent for water oxidation compared to either of the two compounds individually. We discuss possible electron-hole separation mechanisms in two semiconductors comprising a primary photon-absorbing semiconductor of CuWO4 with a secondary semiconductor of WO3. When the WO3/CuWO4 composite is simultaneously irradiated, the photogenerated hole from the WO3 valence band transfers to CuWO4, which results in an enhanced charge separation of CuWO4. Furthermore, the OER catalytic activity of manganese phosphate (MnPO) was compared to manganese oxide nanoparticles (Mn2O3) by electrochemical measurements, showing that the manganese phosphate was more efficient for the OER reaction. To investigate the effect of catalysts on semiconductors, manganese phosphate was deposited on the WO3/CuWO4 composite. The result demonstrates the promise of manganese phosphate for improving the photocurrent as well as the stability of the WO3/CuWO4 composite.
authors.affiliation: Department of Chemistry, Mokpo National University , Jeonnam 534-729, Korea.
authors.forename: Ki Min
authors.initials: KM
authors.lastname: Nam
authors.affiliation: Department of Chemistry, Mokpo National University , Jeonnam 534-729, Korea.
authors.forename: Eun Ah
authors.initials: EA
authors.lastname: Cheon
authors.affiliation: Department of Chemistry, Mokpo National University , Jeonnam 534-729, Korea.
authors.forename: Won Jung
authors.initials: WJ
authors.lastname: Shin
authors.affiliation: Center for Electrochemistry, Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Allen J
authors.initials: AJ
authors.lastname: Bard