Herein, a kind of three-dimensional hollow Mg-Ca-Al hydrotalcite-like compounds (HTLCs) microsphere was prepared by self-assembly of hydrotalcite-like nanosheets. Mg-Ca-Al HTLCs microsphere (MS) has large specific surface area and large pore size, and the modification of KF·2H2O increases numerous alkaline active sites on the surface of the catalyst. The prepared catalyst has excellent catalytic effect for the production of biodiesel by transesterification. Under the optimal conditions of the catalyst addition amount which accounts for 2% of the weight of oil, the biodiesel yield of the best catalyst is as high as 92% within 30 minutes. This article also provides a paradigm of a rational structural design for regulating the morphology of HTLCs.
Controllable deposition of nanosphere with zeolitic imidazolate frameworks (ZIFs) is an efficient method to achieve unique properties and create new types of multifunctional ZIF core–shell materials with enhanced properties. Core‐shell ZIF‐67@CeO2 nanosphere was designed with ZIF‐67 nanoparticles as seed for the deposition of CeO2 nanocrystals. The as‐prepared ZIF‐67@CeO2 nanosphere can catalyze CO2 cycloaddition reaction with significant activity. The synergistic acid‐base catalytic sites of ZIF‐67@CeO2 nanosphere were investigated through TPD analysis. These sites can effectively coordinate and activate the substrate molecules, thereby enhancing catalytic efficiency for CO2 cycloaddition reaction. The ZIF‐67@CeO2 nanosphere showed almost 100.00 % conversion of styrene oxide and 100.00 % selectivity of desired cyclic carbonate (120 °C, 7.5 bar, and 8 h). In addition, ZIF‐67@CeO2 showed a negligible decrease in the catalytic activity even after being reused for four cycles.
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