Enhancing HT-WGS catalyst performance with stable monovalent copper species via electron supply from defect-induced MgO.

Magnesium oxide (MgO) exhibits excellent synergy with cerium oxide (CeO 2), serving as either textural or electronic promoters during catalytic reactions. However, achieving well-dispersed CeO 2 -MgO is technically challenging because they are known not to form solid solutions, and the crystal growth of CeO 2 suppresses the structure formation of MgO, leading to MgO being in an inhomogeneous amorphous state within CeO 2 -MgO. For this reason, most of research groups have been struggling with synthesizing well-dispersed CeO 2 -MgO. This leads them to focusing on the interaction between the active metal and cerium, overlooking the true role of magnesium. In this study, we successfully synthesized well-dispersed CeO 2 -MgO via a spray pyrolysis-assisted evaporation-induced self-assembly method, followed by the impregnation of Cu. The location and dispersion of Cu nanoparticles were highly dependent on the MgO distribution. Additionally, we revealed that this significantly influenced the catalytic activity and stability towards the HTS reaction and furthermore supplies electrons to monovalent Cu species, helping maintain the stable electron structure and oxidation state of Cu species considered as active sites. These findings suggest that optimizing the MgO distribution in CeO 2 -MgO is a promising strategy for developing efficient catalysts for the HTS reaction, emphasizing the role of MgO in designing high-performance catalysts. [Display omitted] • Investigation of the true role of MgO in CeO 2 -MgO support for Cu-based HTS catalysts. • Cu particles are mainly located around MgO in CeO 2 -MgO support. • MgO distributions highly influenced on the Cu particle size, dispersion, and redox ability. • Defect-induced MgO supplies electrons to Cu active sites, enhancing catalytic performance. [ABSTRACT FROM AUTHOR]