Novel non-thermal plasma based strategy to synthesize high-performance multistage mesoporous cobalt-ceria oxides for plasma-catalytic decomposition of environmentally hazardous acetone.

A non-thermal plasma based treatment strategy is proposed to prepare CoCeOx catalysts using metal-organic frameworks (MOFs) as precursor, which were synthesized by a simple NaOH-mediated method through an organometallic reaction of Co2 + /Ce4+ ions and benzimidazole in the presence of polyvinylpyrrolidone. The obtained catalysts exhibited large specific surface areas and retained the morphological and structural features of the MOF precursors. The activity of the catalysts in the degradation of acetone was investigated using a post-plasma catalytic (PPC) setup and a possible degradation pathway, using the CoCeOx catalyst, was proposed. The synergy between Co and Ce ions resulted in a better activity of the CoCeOx catalysts compared to the CoOx catalysts and an increased specific surface area of the CoCeOx catalysts. Among all CoCeOx catalysts studied, the Co0.7Ce0.3Ox catalyst exhibited the highest acetone removal efficiency, whereas a further increase in the Ce content led to a decrease in the conversion when the Co/Ce ratio exceeded 7:3. DFT calculations reveal that Co doped CeO2 surface is conducive to capturing acetone and Co3O4 surface helps to decompose O3 and form active oxygen. DRIFTS analyses prompt that acetic acid, which are the main intermediates, are difficult to decompose only by catalysts, while they can be effectively decomposed with the addition of plasma. This study thus offers a novel low temperature strategy in synthesizing Co and Ce based bimetallic oxide catalysts for efficient plasma-catalytic degradation of volatile organic compounds.