Pr-doped CeO₂ from MOF templates exhibits enhanced catalytic performance for dimethyl carbonate synthesis from CO₂ and methanol, driven by increased oxygen vacancies and improved acidic/basic properties.

Due to the increasing attention focused on global warming, many studies on reducing CO₂ emissions and developing sustainable energy strategies have recently been performed. One of the approaches is CO₂ methanation, transforming CO₂ into methane. Such transformation (CO₂ + 4H₂ → CH₄ + 2H₂O) provides advantages of carbon liquification, storage, etc. In this study, we investigated CO₂ methanation on nickel–magnesium–alumina catalysts both experimentally and computationally. We synthesized the catalysts using a precipitation method, and performed X-ray diffraction, temperature-programmed reduction, and N₂ adsorption–desorption tests to characterize their physical and chemical properties. NiAl₂O₄ and MgAl₂O₄ phases were clearly observed in the catalysts. In addition, we conducted CO₂ hydrogenation experiments by varying with temperatures to understand the reaction. Our results showed that CO₂ conversion increases with Ni concentration and that MgAl₂O₄ exhibits high selectivity for CO. Density functional theory calculations explained the origin of this selectivity. Simulations predicted that adsorbed CO on MgAl₂O₄(100) weakly binds to the surface and prefers to desorb from the surface than undergoing further hydrogenation. Electronic structure analysis showed that the absence of a d orbital in MgAl₂O₄(100) is responsible for the weak binding of CO to MgAl₂O₄. We believe that this finding regarding the origin of the CO selectivity of MgAl₂O₄ provides fundamental insight for the design methanation catalysts.

Macro-porous alumina was used as a support for a pellet-type Cu-based desulfurization sorbent in the gas purification process for producing blue hydrogen by the gasification of petroleum coke. The effects of the macro-porous alumina on the pellet-type sorbents in reducing the gas diffusion resistance into the pores were investigated. The results showed that the macro-porous alumina enhances the diffusion resistance, resulting in an improved sulfur capacity of CuO absorbents. Such effects were more significant on the pellet type CuO absorbents than the powder type. In addition, CO production was observed experimentally during the desulfurization reaction of carbonyl sulfide (COS) at low temperatures (~473 K). Density functional theory calculations were also performed to understand the kinetics of desulfurization and CO production. The simulation results predicted that the kinetics of desulfurization is strongly affected by the local surface environment. The CO generated from C–O bond breaking from COS had a lower adsorption energy than the CO₂ formation. These results suggest that the Cu-based desulfurization sorbent has potential catalytic activity for producing CO from COS dissociation.

This study applied the lattice expansion strategy to enhance the performance of the CuMn ₂ O ₄ oxygen carrier.