One pot solution combustion synthesis of highly mesoporous hematite for photocatalysis

Iron oxides were synthesized by solution combustion synthesis using glycine (fuel) and ferric nitrate (oxidizer) as raw materials. The effects of the fuel to oxidizer ratio, ϕ, on the combustion behavior, phase, morphology and surface area of the products were systematically studied. Pure hematite was synthesized directly by the combustion of the precursors under fuel-lean conditions in one step without further heat treatment, simply by selecting a proper fuel to oxidizer ratio, ϕ. The hematite has a highly mesoporous structure with specific surface area of 103 m2 g-1 and an average size of about 20 nm, which was obtained at ϕ=0.3. The hematite displays a continuous absorption band in the visible region. The photocatalytic activity of the hematite was evaluated by degrading the methylene blue pollutant in water at ambient temperature. The synthesized mesoporous hematite is a promising visible light photocatalysts for organics decomposition.