Improvement of hydrothermal stability of zeolitic imidazolate frameworks

The metal-organic framework ZIF-8, which undergoes hydrolysis under hydrothermal conditions, is endowed with high water-resistance after a shell-ligand-exchange-reaction. The stabilized ZIF-8 retains its structural characteristics with improved application performances in adsorption and membrane separation. © 2013 The Royal Society of Chemistry

An Overview of Recent Development in Composite Catalysts from Porous Materials for Various Reactions and Processes

Catalysts are important to the chemical industry and environmental remediation due to their effective conversion of one chemical into another. Among them, composite catalysts have attracted continuous attention during the past decades. Nowadays, composite catalysts are being used more and more to meet the practical catalytic performance requirements in the chemical industry of high activity, high selectivity and good stability. In this paper, we reviewed our recent work on development of composite catalysts, mainly focusing on the composite catalysts obtained from porous materials such as zeolites, mesoporous materials, carbon nanotubes (CNT), etc. Six types of porous composite catalysts are discussed, including amorphous oxide modified zeolite composite catalysts, zeolite composites prepared by co-crystallization or overgrowth, hierarchical porous catalysts, host-guest porous composites, inorganic and organic mesoporous composite catalysts, and polymer/CNT composite catalysts

Synthesis and characterization of ERB-1 zeolite

The ERB-1 zeolite was synthesized using silica aerogel as the silica source, boric acid as the boron source, and sodium hydroxide as the alkali source, respectively. The obtained ERB-1 zeolite was characterized by X-ray diffraction (XRD), N-2 adsorption, NH3 temperature-programmed desorption (NH3-TPD), thermogravimetry analysis (TG), differential thermal analysis (DTA) and Fourier-transform infrared reflectance spectroscopy (FT-IR). It was found that the suitable synthesis gel compositions were n(SiO2)/n(B2O3) = 0.6 similar to 2, n(H2O)/n(SiO2) = 40, n(NaOH)/n(SiO2) = 0.1 similar to 0.2, and n(HMI)/n (SiO2) = 0.8 similar to 1. The FT-IR result indicated that a part of boron atoms had incorporated into the framework of ERB-1 zeolite. The TG, DTA, and XRD results showed that the ERB-1 zeolite maintained its framework below 800 degrees C when it was calcined in air flow. The NH3-TPD result exhibited that the ERB-1 zeolite had poor acidity and the weak acid was in the majority of its acid sites