Selective liquid phase benzyl alcohol oxidation over Cu-loaded LaFeO3 perovskite

Abstract

Copper loaded LaMO₃ (M = Mn, Fe and Co) perovskites have been synthesized by a single-step solution combustion method. These materials have been investigated for liquid phase oxidation of benzyl alcohol using tertiary butyl hydrogen peroxide (TBHP) as oxidant in air at 80 °C under ambient pressure. Among these, the 10 at% Cu-loaded LaFeO₃ has shown the best activity i.e., ∼99% conversion with complete benzaldehyde selectivity. The formation of perovskite phase was confirmed from XRD and the presence of Cu²⁺ was confirmed by XPS analysis. The higher activity of the combustion synthesized catalyst has been ascribed to the presence of a poorly defined surface structure containing an amorphous CuO phase wrapping the LaFeO₃ particle, as evidenced from the HRTEM analysis. The catalyst recycling tests have shown a negligible loss of activity in the consecutive cycles.