Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2007 · 14 citations · 0 references
Natural SciencesChemical EngineeringMaterials ScienceElectrochemical EngineeringElectrochemistryEnergy MaterialsPhotocatalysisPhotochemistryPhotoelectrochemical MaterialsPhotoelectrochemistrySolar CellsSolar Energy SystemsDye-sensitized Solar CellsHydrogen ProductionPhotocatalytic MaterialsPhotocatalytic Water SplittingPhotoelectrochemical CellsPhotoelectrochemical Water SplittingSolar Energy ConversionVisible-light Photocatalysis
Photocatalytic and photoelectrochemical approaches to solar hydrogen production in our group were introduced. In photocatalytic water splitting system using NiO<sub>x</sub>/ TiO<sub>2</sub> powder photocatalyst with concentrated Na<sub>2</sub>CO<sub>3</sub> aqueous solution, solar energy conversion efficiency to H<sub>2</sub> and O<sub>2</sub> production (STH efficiency) was 0.016%. In addition, STH efficiency of visible light responding photocatalyst, NiOx/ promoted In<sub>0.9</sub>Ni<sub>0.1</sub>TaO<sub>4</sub>, was estimated at 0.03%. In photoelectrochemical system using an oxide semiconductor film phptoelectrode, STH efficiencies of meosporous TiO<sub>2</sub> (Anatase) , mesoporous visible light responding S-doped TiO<sub>2</sub> (Anatase) and WO<sub>3</sub> film were 0.32-0.44% at applied potential of 0.35 V vs NHE, 0.14% at 0.55 V and 0.44% at 0.9 V, respectively. Finally, solar hydrogen production by tandem cell system composed of an oxide semiconductor photoelectrode, a Pt wire counter electrode and a dye-sensitized solar cell (DSC) was investigated. As photoelectrodes, meosporous TiO<sub>2</sub> (Anatase), mesoporous S-doped TiO<sub>2</sub> (Anatase), WO<sub>3</sub>, BiVO<sub>4</sub> and Fe<sub>2</sub>O<sub>3</sub> film were tested. STH efficiency of tandem cell system composed of a WO<sub>3</sub> film photoelectrode, and a two-series-connected DSC (Voc = 1.4 V) was 2.5-2.8%. In conclusion, it is speculated that more than 5% STH efficiency will be obtained by tandem cell system composed of an oxide semiconductor photoelectrode and a two-series-connected DSC in near future. This suggests a cost-effective and practical application of this system for solar hydrogen production.