Enhanced transformation of CO₂ over microporous Ce-doped Zr metal-organic frameworks

Metal-organic frameworks (MOF) have been studied extensively for the adsorption and catalytic conversion of CO₂. However, previous studies mainly focused on the adsorption capabilities of partially or totally Ce substituted UiO-66, there are few studies focusing on transformation of the structure and catalytic activity of these materials. In this work, a series of Zr/Ce-based MOFs with UiO-66 architecture catalysts were prepared for the conversion of CO₂ into value-added dimethyl carbonate (DMC). Owing to the different addition order of the two metals, significantly varied shapes and sizes were observed. Accordingly, the catalytic activity is greatly varied by adding a second metal. The different catalytic activities may arise from the different acid-base properties after Ce doping as well as the morphology and shape changes. Besides, the formation of terminal methoxy (t-OCH₃) was found to be the rate limiting step. Finally, the reaction mechanism of CO₂ transformation in the presence of a dehydrating agent was proposed.