Exploring the role of promoters (Y, Tb and Gd) in the performance of Co-based catalyst for dry reforming of methane
Dry reforming of methane (DRM) is an effective method for achieving carbon reduction and carbon neutrality by directly converting two greenhouse gases , CH 4 and CO 2 , into value-added products. However, catalysts used in this process are prone to metal sintering and carbon deposition , which are major obstacles. Thus, the design of high-performance catalysts is crucial for the success of dry reforming technology. In this paper, a series of Co-based catalysts modified with different rare earth metals (Y, Tb, Gd) and γ-Al 2 O 3 as the support were prepared using the conventional co-impregnation method. The effects of the introduction of rare earth metals additives on the activity and resistance to carbon build-up of the catalysts were investigated. The catalysts were analyzed using various characterization techniques. The results showed that Y and Tb as additives could effectively improve the activity and stability of the catalyst. However, the Gd modified Co-based catalyst had a large specific surface area but was less favorable for the DRM reaction. The best performance catalyst was achieved with the 10Co–5Y/γ-Al 2 O 3 under 750 °C with CH 4 and CO 2 conversions of 91.79% and 98.33%, respectively. This is mainly due to the fact that the introduction of Y enhances the electron transfer between Co and metal oxides , generating more oxygen vacancies and base vacancies on the surface, thus enhancing the adsorption and activation of CO 2 . The 10Co–5Y/γ-Al 2 O 3 catalyst demonstrated excellent DRM performance even after 20 h at 750 °C. Moreover, we proposed a hypothesis regarding the mechanism of resistance to carbon build-up. This study provides a reasonable idea to design Co-based catalysts with resistance to sintering and carbon accumulation to improve the performance of reforming catalysts.
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