Exploring the role of promoters (Y, Tb and Gd) in the performance of Co-based catalyst for dry reforming of methane

• Published in: International journal of hydrogen energy Vol. 48; no. 97; pp. 38251 - 38265
• Main Authors: Cai, Yajing, Zhang, Guojie, Liu, Jun, Zhang, Yunfei, Li, Tianshan, Zhang, Xiaodi, Wang, Ying, Zhao, Yuqiong, Li, Guoqiang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.12.2023
• Subjects: Carbon deposition; Cobalt; DRM; Promoters; Carbon deposition; Cobalt; Promoters; DRM
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2023.06.152

Dry reforming of methane (DRM) is an effective method for achieving carbon reduction and carbon neutrality by directly converting two greenhouse gases, CH4 and CO2, 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-Al2O3 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-Al2O3 under 750 °C with CH4 and CO2 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 CO2. The 10Co–5Y/γ-Al2O3 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. [Display omitted] •The introduction of Y and Tb enhances the electron transfer ability of Co species.•The introduction of Y improves the cobalt dispersibility and oxygen vacancies.•30% enhancement in CH4 and CO2 conversion was achieved with 10Co–5Y/γ-Al2O3.•The mechanism of resistance to carbon build-up was proposed.