Reshaping the Role of CO₂ in Propane Dehydrogenation: From Waste Gas to Platform Chemical

This is the authors' abstract. We don't add key points for this paper.

The valorization of CO 2 appeals to the chemical industry due to the reduction in greenhouse gas emissions and the ability to offer more renewable products. Propylene production is the second largest process in the chemical industry, and it strongly depends on fossil fuel feedstocks. Coupling CO 2 reduction with propane dehydrogenation boosts conversion and produces CO, a valuable platform chemical currently synthesized by fossil-methane reforming. In this work, (i) we demonstrate the environmental benefits of coupling CO 2 with a life-cycle assessment under industrial conditions, potentially reducing emissions by 3 t CO2-eq per ton of propylene produced. (ii) We screen supported catalytic materials─both known and novel─with a focus on propane and CO 2 reaction mechanisms under industrial reaction conditions of 400–700 °C and pressures of 1–6 barg (redox: V, Galinstan, In, Mo, Mn, Bi, Sb, Ta; nonredox: Cr, Ga, co, Al, Zn, Au, Zr, Ag, W, La, Cu; and some alloy combinations). We evaluate each material under the kinetic regime, and we quantify reaction, side reaction, and deactivation kinetics (coking, cracking, and dry-reforming), as well as the regeneration ability. We then classify them based on their dominant mechanisms (direct CO 2 assistance or indirect with H 2 via reverse water gas shift) and identify each catalyst’s strengths and weaknesses. Finally, (iii) we correlate our database of experimental results of 22 active metals/metal oxides with the Tamman temperature and density functional theory (DFT)-based oxygen vacancy formation energies. We discovered that oxygen mobility plays a crucial role in the kinetics of reoxidation with CO 2 and the overall balance of active sites related to dehydrogenation and reoxidation.