Promotion of low-temperature Ni-based CO2 methanation catalysts by LaOx confined in mesoporous silica channels

Converting CO 2 from the coal chemical industry into natural gas via methanation reaction, coupled with green hydrogen, is a promising strategy for reducing carbon emissions. While Ni-based catalysts are cost-effective and widely used for CO 2 methanation, their performance is often hindered by low temperatures activity. We confined LaO x species within the mesoporous silica (mSiO 2 ) channels to serve as a support for Ni-based CO 2 methanation catalysts. The results demonstrate that LaO x introduction (3.9 wt%) significantly improves CO 2 conversion from 38.2 % to 74.4 %, while enhancing CH 4 selectivity from 94.8 % to 99.7 % at 300 °C. Interestingly, excessive La loading does not noticeably reduce the promotion efficiency. Detailed characterization revealed that ultrafine LaO x species anchored within silica framework improved the dispersion and reduction of Ni nanoparticles and served as strong basic sites to promote CO 2 dissociation. In-situ DRIFT and isotope studies demonstrated that LaO x facilitated the hydrogenation of formate intermediates, enhancing both CO 2 conversion and CH 4 selectivity. In addition, LaO x endowed the support with hydrogen spillover capability, enabling active H from Ni nanoparticles to migrate to LaO x sites and accelerate the conversion of formate intermediates into CH 4 . These results underscore the potential of LaO x -modified mesoporous silica to optimize Ni-based catalysts, offering valuable guidance for the design of high-performance CO 2 hydrogenation catalyst supports.