Combining exsolution and photothermal chemistry for mid-temperature chemical looping dry reforming of methane

The production of syngas from the methane and carbon dioxide by the chemical looping dry reforming of methane (CL-DRM) offers a promising pathway for efficient use of methane while mitigating the greenhouse gas effect. However, the high methane activation energy and product selectivity require the reaction to be carried out at high temperatures, which not only consumes a large amount of thermal energy, but also exposes the oxygen carriers to prolonged high-temperature stress, affecting their long-term stability. Thus, we propose to combine the exsolution and photothermal chemistry strategies to reduce the reaction temperature of the CL-DRM. Experimental results show that photothermal CL-DRM achieves a 19 % methane conversion enhancement relative to thermal CL-DRM, and its reaction temperature is reduced by 320 °C. This is attributed to the effective photoactivation and enhanced lattice oxygen vibrations that reduce the apparent activation energy of the reaction. It is shown that the combination of wavelength and temperature needs to be considered when light illumination and heat are added together to the reaction system. This study significantly reduces the temperature of the chemical looping dry reforming reaction, which will contribute to its further practical application.