Lewis Acid Sites in MOFs Supports Promoting the Catalytic Activity and Selectivity for CO Esterification to Dimethyl Carbonate
CO esterification to dimethyl carbonate (DMC) is an attractive route, while the catalyst is the main problem to restrict the industrialization of this route. The supported palladium catalysts have been often used for this route. However, the effect of support is always unclear. In this work, we have firstly introduced three metal-organic frameworks (MOFs) materials as catalyst supports, such as UiO-66, MIL-101 and MOF-5, and studied the effect of Lewis acid sites in MOFs supports on the catalytic activity and selectivity for CO esterification to DMC. Interestingly, the Pd(II)/UiO-66 catalyst exhibits superior catalytic performance with 87.9% CO conversion and 98.5% DMC selectivity than the other catalysts due to the abundant Lewis acid sites in UiO-66. It was proved that UiO-66 with more defects would have a large amount of Lewis acid sites, and the catalytic performance was positively correlated with the amount of Lewis acid sites in MOFs supports, which can be demonstrated by the characterizations of NH3-TPD, Pyridine-IR, XPS and in situ DRIRS. Current work not only revealed the relationship between supports Lewis acidity and catalytic performance, but also promoted to develop practical catalysts for CO esterification to DMC.