Catalyst design for selective CO2 hydrogenation to light olefins: engineering active phases and interfaces to steer intermediate evolution.

Catalytic hydrogenation of CO2 to light olefins (C=2-C=4) offers a promising route for converting CO2 into high-value platform chemicals while reducing reliance on fossil feedstocks. Its practical implementation, however, is hindered by the thermodynamic and kinetic stability of CO2, competing reaction pathways, and the challenge of promoting selective C-C coupling while suppressing CO, CH4 and heavier hydrocarbons. This review critically examines catalyst design through the regulation of key reaction intermediates in two principal pathways, i.e., Fe-based Fischer-Tropsch synthesis and methanol-mediated tandem conversion. For Fe-based catalysts, promoter engineering, support effects, oxygen vacancies, and metal-support interactions are discussed in relation to FeOx/FeCx phase evolution, CO2 activation, surface C/H balance, and chain growth. For oxide-zeolite tandem catalysts, active-site matching, acidity control, interfacial proximity, and diffusion are examined in terms of oxygenate conversion, hydrocarbon-pool chemistry, olefin selectivity, and catalyst stability. Across both pathways, intermediate regulation, multiphase interface engineering, hydrogen management, and deactivation control emerge as central principles for developing efficient, selective, and durable catalysts for CO2 valorisation to light olefins.