Unique Phase Evolution and Multielemental Effects in Natural Rhodochrosite for Methane Oxidation

Rhodochrosite, a naturally occurring ${\mathrm{MnCO}}_3$ -based mineral with inherent compositional complexity, is investigated as a catalyst for methane oxidation. The material exhibits distinctive catalytic behavior, including enhanced $C_2$ hydrocarbon formation and selective CO production, attributed to its multielemental composition and dynamic phase transformations under reaction conditions. In particular, rhodochrosite suppresses CO formation while enhancing $C_2{H}_4$ production compared to pure ${\mathrm{MnCO}}_3$ , the primary component of rhodochrosite. Thermal treatment converts rhodochrosite into mixed manganese oxide phases ( ${\mathrm{Mn}}_2{O}_3$ , ${\mathrm{Mn}}_3{O}_4$ ), while trace elements and mineral impurities are retained and may influence oxide phase evolution and catalytic behavior. These findings highlight the potential of natural multicomponent minerals as compositionally diverse, phase-adaptive platforms for selective methane conversion.