Recent Advances in CO2 Hydrogenation to Light Olefins
The catalytic hydrogenation of carbon dioxide (CO2) to light olefins (C2–C4) represents a pivotal route for mitigating greenhouse gas emissions while producing high-value chemical feedstocks. This review systematically examines the two principal technological pathways: CO2-Fischer-Tropsch synthesis (CO2-FTO) and CO2-methanol-to-olefins (CO2-MTO). The CO2-FTO route couples reverse water-gas shift (RWGS) with Fischer-Tropsch synthesis, whereas CO2-MTO proceeds via methanol intermediate. Key challenges arise from the thermodynamic stability of CO2 (C=O bond dissociation energy ~750 kJ/mol) and kinetic limitations. The review critically evaluates the influence of catalyst promoters (e.g., Na, Mn, Cu), support structures, and surface defect site concentrations on CO2 activation and olefin selectivity. For zeolite-based catalysts, pore architecture and acidity are shown to govern methanol conversion to olefins. Representative data from the literature indicate that Fe-based catalysts with Na promotion achieve CO2 conversion up to 40% with olefin selectivity exceeding 50% under optimized conditions. The review underscores the necessity of integrating catalyst design with reactor engineering to overcome thermodynamic constraints and achieve industrially viable performance.