Photochemical hydrogen production from a water-methanol mixture with small particles of iron oxide suspensions

Abstract

Photochemical hydrogen production has been detected from small particles of doped iron oxide in a methanol-water (1:1) mixture. The systems studied consisted of a pure n-type semiconductor, Fe 2−xNb xO 3 (x=0.02), a pure p-type semiconductor, La 1−xSr xFeO 3 (x=0.25), and Mg-doped α-Fe 2O 3. This system was found to be heterogeneous, consisting of both spinel and corundum phase iron oxides, and shows a much higher activity than the pure single phase systems, with either corundum (α-Fe 2O 3) or spinel (Fe 3−xMg xO y) structure. The efficiency of the reaction increased substantially when the powders were loaded with Pt. Hydrogen production from these Mg-doped iron oxides is photo-ocatalytic and occurs mainly as a result of bandgap irradiation, but also occurs with sub-bandgap illumination in small amounts. There is a linearly increasing dependence of the H 2 production with increasing light intensity.