K-doped CuO/ZnO with Synergistic Dual Active Centers for Highly
Efficient Dimethyl Carbonate Synthesis
Abstract
The application of heterogeneous catalysts in dimethyl carbonate (DMC)
synthesis from methanol is hindered by low activation efficiency of
methanol to methoxy intermediates (CH3O*), which are the key
intermediates for DMC generation. Herein, a catalyst of alkali metal K
anchored on the CuO/ZnO oxide is rationally designed for offering Lewis
acid-base pairs as dual active centers to improve the activation
efficiency of methanol. Characterizations of CO2-TPD,XPS and DRIFTS
revealed that the addition of Lewis base K observably boosted the
dissociation of methanol and combined with Lewis acid CuO/ZnO oxide to
stably adsorb the formed CH3O*, thus synergistically promoted the
transesterification. Finally, the CuO/ZnO-9%K2O catalyst exhibited the
optimal catalytic activity, achieving a high yield of 74.4% with an
excellent selectivity of 98.9% for DMC at a low temperature of 90 °C.
The strategy of constructing Lewis acid-base pairs provides a reference
for the design of heterogeneous catalysts.