Refining catalytic oxidation of volatile organic compounds over Gd-Sr-Co perovskite-based oxides fabricated via viscous mixture induction: Unveiling the crucial factors influencing catalytic activity

Abstract

A series of Gd-Sr-Co perovskite-based oxides have been successfully synthesized by thermally driving viscous mixture, wherein only very trace amounts of water need and the metal salts powders do not need to be thoroughly mixed. By the characterization of XRD, XPS, EPR, and Raman, the levels of oxygen vacancies, lattice oxygen, and adsorbed oxygen in the catalyst are controlled by varying the amount of Sr doping. Unlike traditional conclusions, we found that the catalytic activities of the catalysts did not enhance with the increase in the contents of adsorbed oxygen and oxygen vacancies. H2-TPR and O2-TPD confirmed that the migration of lattice oxygen in catalysts determined their activities. Comparative activity of individual catalysts was evaluated by catalytic oxidation of toluene. The best active catalyst also showed superior catalytic activity for the oxidation of acetone, ethyl acetate, and chlorobenzene. The effects of humidity and weight hourly space velocity on the stability of the catalyst were also evaluated. Catalyst’s surface structural changes in toluene oxidation were also analyzed by in-situ DRIFTS. This study provides a simple approach to tailor perovskite-based oxide structures, crucial for effective catalytic oxidation of VOCs.