Enhanced low-temperature catalytic activity for CO2 methanation over NiMgx/Na-HNTs: The role of MgO

CO2 methanation over Ni-based catalysts provides a promising way to address the energy crisis and the environmental problems caused by massive CO2 emissions. Nevertheless, Ni-based catalysts still face the challenges of poor activity at low temperatures. Herein, a series of MgO-promoted Ni-based catalysts supported by HNTs (halloysite nanotubes) were successfully prepared to investigate the role of MgO in CO2 methanation. Various characterization results demonstrated that introducing MgO can enhance metal-support interaction, resulting in generating finer and more stable metal particles. Meanwhile, MgO can also offer sufficient alkaline sites and oxygen vacancies for CO2 activation. NiMg1.0/Na-HNTs exhibited the maximum CO2 conversion (79.0%) and CH4 selectivity (97.5%) even at 275 degrees C as well as outstanding long-term stability over 100 h reaction. Additionally, in situ DRIFTS suggested that the mechanism for CO2 methanation in this work mainly followed the formate pathway, and introducing magnesium can accelerate to convert intermediates. Briefly, this study provides an efficient low-temperature catalyst for CO2 methanation with potential industrial applications.