Surface basic site effect on CoLa/m-Al2O3 catalysts for dry reforming of methane

Dry reforming of methane (DRM) is a novel technology that enables the direct utilization of greenhouse gases (CH 4 and CO 2 ) for the production of value-added products. In the DRM reaction, the acid-base characteristics of the catalyst support play a pivotal role in determining the performance of the catalyst. In this study, a series of Co-based catalysts with different alkali earth metal-modified Al 2 O 3 composite supports, specifically m-Al 2 O 3 (m=Ca, Mg, and Ba), were prepared using the impregnation method. Various characterization techniques were employed to investigate the impact of alkaline site modulation on the support surface with respect to anti-sintering and anti-coking properties. The results demonstrate that the m-Al 2 O 3 composite support catalysts, prepared with Mg and Ca modulation, exhibit an abundance of basic sites and oxygen vacancies. This promotes the adsorption and activation of CO 2 , enhances the rate of carbon elimination, and effectively addresses carbon deposition and metal sintering issues. Notably, the CoLa/Mg-Al 2 O 3 catalyst shows the highest performance under reaction conditions of 750 °C, with CH 4 and CO 2 conversions reaching 92.3 % and 97.5 %, respectively. On the other hand, the CoLa/Ba-Al 2 O 3 catalysts display poor performance in dry reforming. Kinetic studies indicate that CoLa/Mg-Al 2 O 3 catalyst significantly reduce the apparent activation energy required for CH 4 and CO 2 cracking. Furthermore, it is demonstrated that the introduction of alkali earth metals can promote the dissociation of CH 4 and CO 2 .