Solar fuel synthesis based on colloidal and particulate semiconductors. Annual report, 1 August 1983-31 July 1984

The properties of a new and very active oxygen-evolving dimeric complex L2(H2O)Ru-O-Ru(H2O))L2 (where L = 2,2'-bipyridyl-4,4'-dicarboxylate) were scrutinized. Stable and very reactive H2-evolving photosystems based on the linear-chain complex (Pt(bpy)2)(Pt(CN)4) were characterized. The scale-up of one photosystem produced significant quantities of gas. The pathway of room temperature methanation of CO2 on TiO2-supported mixed Ru/RuO2 catalyst was studied by FTIR spectroscopy. The same material was found to enhance drastically the Boudard disproportionation and the conversion of NO and CO to CO2 and N2O. A MoO3/TiO2 catalyst was discovered that displays high activity in the photoactivation of methane at 40 deg C. An efficient room temperature photocatalyst Pt(bpy)-TiO2 was also discovered for selectively oxidizing methanol to formaldehyde, a valuable chemical feedstock. An unprecedented light-to-current conversion efficiency of 91% was achieved in sensitizing fractal-type semiconductor oxide films. Regenerative photoelectrochemical cells based on Al-doped anatase films and the Br(1-)/Br2 redox couple were scaled up to 32 sq cm surface area. An open-circuit voltage of 1.05 V, a fill factor of 73% and a polychromatic light-to-power conversion efficiency of 3.5% were obtained with the system.