Research progress in catalyst modification strategies for CO₂ hydrogenation to light olefins

The continuous growth of carbon dioxide （CO₂） emissions exacerbates global ecological degradation, leading to a series of environmental issues such as climate change and ocean acidification. Reducing CO₂ emissions has therefore become a critical challenge for sustainable development. Light olefins, serving as essential feedstocks and platform molecules in the chemical industry, are widely used to produce various value-added chemicals. Unlike conventional feedstocks and processes for olefin synthesis, the conversion of CO₂ into light olefins not only enables resource utilization of CO₂ but also reduces dependence on petroleum resources, representing a promising approach that benefits the environment, energy security, and the economy. Currently, two main pathways for CO₂ hydrogenation to light olefins are widely reported: the CO₂-Fischer-Tropsch to Olefins （CO₂-FTO） pathway via CO as an intermediate, and the CO₂-Methanol to Olefins （CO₂-MTO） pathway via methanol. The CO₂-FTO pathway achieves high CO₂ conversion, but the C—C coupling is uncontrollable, resulting in a product distribution that follows the Anderson-Schulz-Flory （ASF） model, which limits the selectivity toward light olefins. In contrast, the CO₂-MTO pathway breaks the ASF distribution constraint and enables higher light olefin selectivity; however, it suffers from low CO₂ conversion and high CO byproduct selectivity. This review systematically summarizes the reaction processes, mechanisms, and catalyst modification strategies employed to enhance catalytic performance for both pathways. For the CO₂-FTO route, modification strategies primarily focus on Fe-based catalysts, including the doping of promoters （e.g., alkali metals, transition metals） and the optimization of supports （e.g., oxides, carbon materials）. For the CO₂-MTO route, strategies are discussed from three perspectives: metal oxides, zeolites, and their coupling methods. Additionally, a recently reported alternative pathway （i.e., RWGS followed by CO hydrogenation） is briefly outlined. Finally, the advantages and limitations of different modification strategies across pathways are summarized, and future research directions are proposed. Overall, CO₂ hydrogenation to light olefins represents a sustainable chemical production route with broad prospects for development.