Experimental and theoretical study of the intrinsic kinetics for dimethyl ether synthesis from CO 2 over Cu–Fe–Zr/HZSM‐5

An intrinsic kinetics model was established for CO 2 hydrogenation to dimethyl ether (DME) with a Cu–Fe–Zr/HZSM‐5 catalyst based on H 2 /CO 2 adsorption, simulation, and calculation of methanol synthesis from CO 2 intermediates and experimental data. H 2 /CO 2 ‐temperature programmed desorption results show a dissociative H 2 adsorption on Cu site; CO 2 was linearly adsorbed on Fe 3 O 4 weak base sites of the catalyst; the adsorbing capacity of H 2 and CO 2 increased after Zr‐doping. Density functional theory analysis of methanol synthesis from CO 2 and H 2 revealed a formate pathway. Methanol synthesis was the rate‐limiting step (173.72 kJ·mol −1 activation energy) of the overall CO 2 hydrogenation reaction, and formation of H 2 CO is the rate‐determining step of methanol synthesis. Relative errors between calculated and experimental data of partial pressures of all components were less than 10%. Therefore, the kinetics model may be an accurate descriptor of intrinsic kinetics of CO 2 hydrogenation to DME. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1613–1627, 2015