Simultaneously Achieving High Conversion and Selectivity in Syngas-to-Propane Reaction via a Dual-Bed Catalyst System

Given the increase in global carbon emissions, efficientlyconverting syngas into one single C2+hydrocarbon product with low CO2selectivity is important but still challenging. Herein, we report a dual-bedcatalyst system, which can highly convert syngas into propane with lower CO2emissions. Propane in hydrocarbon products can reach 79% at CO conversionof 96% with 12% CO2selectivity. The selectivity of methane is lower than 6% atthe same time. Furthermore, up to 66% propane yield is achieved, which cansignificantly increase the efficiency of carbon utilization compared withtraditional methods. The catalytic performance of the dual-bed reaction systemalso exhibits an excellent stability during the 200 h test on stream. The dual-bedreaction system is configured with a syngas-to-dimethyl ether (DME)CuZnAlOx+ ZSM-5 catalyst in the upper bed and a DME-to-propane SSZ-13 zeolite catalyst in the lower bed. The higher strength of the acid sites forSSZ-13 benefits the formation of propane and helps to limit the cokedeposition. Probing experiments and DFT calculations imply that syngas-to-propane reaction includes methanol-to-olefin processesand subsequent conversion of lower olefins in high-pressure H2. The generated intermediate propylene hydrogenation over SSZ-13leads to a high propane selectivity. This strategy offers a scenario to promote the syngas-to-hydrocarbon performance with low CO2emissions.