Work

Improved Efficiency of CO2 Conversion to Olefins in a Thermal–Microwave Hybrid Heating Reactor

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The catalytic hydrogenation of carbon dioxide into ethylene is an innovative approach to carbon mitigation. However, the process suffers from quick deactivation and low selectivity, thus preventing it from industrial adoption. This study developed a single reactor process with two distinct reaction zones: a conventional heating zone for CO 2 methanation over the Ru/CeO 2 catalyst and a microwave heating zone for methane coupling over the MoO x /CeO 2 catalyst. Microwave irradiation selectively heats active sites on the MoO x /CeO 2 surface, reducing the required energy for initiating C–H bond activation while suppressing the formation of carbonaceous deposits, thus enhancing both the yield and selectivity of the desired products. The structural characteristics of the catalysts were further examined using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and in situ Raman spectroscopy to ascertain changes in the active catalyst phase. The catalyst structure changes were correlated to the activity in CO 2 conversion and ethylene selectivity between the two zones. In the conventional heating zone, 70% CO 2 conversion and 99.5% selectivity for methane have been obtained. In the microwave heating zone set at 600 °C, the formation of ethylene and acetylene was observed. These results demonstrate that hybrid heating of CO 2 conversion to ethylene holds excellent potential for decarbonizing multiple industrial sectors through electrification.

Source: ACS Sustainable Chemistry & Engineering

DOI: 10.1021/acssuschemeng.5c01387