Novel Cu–Fe bimetal catalyst for the formation of dimethyl carbonate from carbon dioxide and methanol

Abstract

A novel Cu–Fe bimetal supported catalytic system was prepared and applied to the direct dimethyl carbonate (DMC) formation from methanol and CO₂. The prepared catalysts were characterized by means of temperature-programmed reduction (TPR), X-ray powder diffraction (XRD), laser Raman spectra (LRS), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD). Metallic Cu, Fe and oxygen deficient Fe₂O_3−x (0 < x < 3) were formed during the reduction and activation step. The supported Cu–Fe bimetal catalysts exhibited good catalytic activity and high stability for the direct DMC formation. Under the reaction conditions at 120 °C and 1.2 MPa with space velocity of 360 h⁻¹, the highest methanol conversion of 5.37% with DMC selectivity of 85.9% could be achieved. The high catalytic performance of the Cu–Fe bimetal catalysts in the DMC formation could be attributed to the interaction of base sites functioned by metallic Cu and Fe with acid sites provided by oxygen deficient Fe₂O_3−x (0 < x < 3) in the activation of methanol and CO₂. The moderate concentration balance of acid and base sites was in favor of DMC formation.