Quasi-isothermal decomposition: a way to nanocrystalline mesoporous-like Fe2O3catalyst for rapid heterogeneous decomposition of hydrogen peroxide

Abstract

Mesoporous-like heterogeneous catalyst, consisting of ultrasmall (<5 nm) amorphous Fe₂O₃ and nanocrystalline γ-Fe₂O₃ possessing surface area of 440 m² g⁻¹ and reaching an enormous rate constant of 70 × 10⁻³ min⁻¹ in hydrogen peroxide decomposition at room temperature, pH of 6.3–6.5 and the catalyst concentration of 1 g L⁻¹ was easily prepared by a one-step quasi-isothermal decomposition (an isothermal decomposition accompanied with a controlled time-limited exotherm) of iron(III) oxalate in air. The non-equilibrium temperature conditions proceeding at the very beginning of the oxalate decomposition proved to be the key factor responsible for the formation of highly efficient combination of nanocrystalline character, large surface area and mesoporous-like nature of the catalyst. The material and catalytic properties of the as-prepared catalyst are discussed and compared to those obtained for our iron(III) oxide-based catalyst (26 × 10⁻³ min⁻¹) prepared earlier by a slow, purely isothermal decomposition of iron(II) oxalate.