Synthesis of the Catalytically Active Mn₃O₄ Spinel and Its Thermal Properties

Abstract

Tetragonal hausmannite (Mn3O4) was synthesized by pulsed-spray evaporation chemical vapor deposition (PSE-CVD) at moderate temperatures. The thermal properties of the obtained Mn3O4 thin films were evaluated with a newly developed in situ emission FTIR method. The performance of Mn3O4 grown on flexible stainless steel mesh substrates was investigated toward the oxidation of CO and C3H6. X-ray diffraction (XRD) patterns, FTIR, and Raman spectroscopy reveal that only the single-phase tetragonal Mn3O4 spinel structure was obtained within the temperature range of 350–500 °C. The as-deposited Mn3O4 is thermally stable up to 800 °C, and its reduction plays a determinant role in the catalytic process. Compared to conventional powder catalysts, the combination of PSE-CVD, in situ emission FTIR, and the flexible substrate provides a novel tool for catalyst synthesis and the evaluation of the thermal properties and catalytic performance.