Recent Advances and Challenges in Single-Atom Catalysts for Thermocatalytic CO2 Hydrogenation.

Abstract

Thermocatalytic hydrogenation of carbon dioxide (CO2) offers a promising route for carbon recycling and sustainable chemical production, yet its efficiency and selectivity are limited by the chemical inertness of CO2 and the structural complexity of conventional heterogeneous catalysts. In recent years, single-atom catalysts (SACs) have emerged as an attractive platform for CO2 hydrogenation due to their atomically defined active sites, high metal utilization efficiency, and tunable electronic structures. This review summarizes recent advances in SACs for thermocatalytic CO2 hydrogenation, with emphasis on structure-activity relationships, reaction mechanisms, and selectivity control toward C1 and economically more valuable C2 + products. We highlight how coordination environment, metal-support interactions, and spatial confinement govern the electron transfer and catalytic performance. Emerging strategies such as cooperative and cascade catalysis, single atom-zeolite coupling, and confinement engineering are emphasized for overcoming intrinsic limitations of isolated single-atom sites. Finally, remaining challenges and future opportunities are outlined, focusing on catalyst stability, scalability, and the rational integration of SACs into industrially relevant catalytic architectures.