Low-Temperature Methane Combustion Using Ozone over Coβ Catalyst

doi:10.1021/jacs.4c05967

Low-Temperature Methane Combustion Using Ozone over Coβ Catalyst

2024-07-20

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DOI：10.1021/jacs.4c05967

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Catalytic methane (CH4) combustion is a promising approach to reducing the release of unburned methane in exhaust gas. Here, we report Co-exchanged beta zeolite (Co beta) as an efficient catalyst for CH4 combustion using O-3. A series of ion-exchanged beta zeolites (Co, Ni, Mn, Fe, and Pd) are subjected to the catalytic test, and Co beta exhibits a superior performance in a low-temperature region (<100 degrees C). The results of X-ray absorption spectroscopy (XAS) and catalytic tests for Co beta with different Co loadings indicate the isolated Co species is the plausible active site. The reaction mechanism of CH4 combustion over the isolated Co2+ cation is theoretically investigated by the single-component artificial force-induced reaction (SC-AFIR) method to thoroughly search for possible reaction routes. The resulting path toward CO2 formation shows an activation energy of 73 kJ/mol for the rate-determining step and an exothermicity of 1025 kJ/mol, which supports the experimental results. During a long-term catalytic test for 160 h without external heating, the CH4 conversion gradually decreases from 80 to 40%, but the conversion fully recovers after dehydration at 500 degrees C (0.5 h). The copresence of H2O and CO exhibits a negative impact on the catalytic activity, while NO and SO2 do not markedly change the catalytic activity.

Keywords:

OXIDATION

DEACTIVATION

PALLADIUM

ZEOLITES

ATOMS

Low-Temperature Methane Combustion Using Ozone over Coβ Catalyst

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