Spray synthesis of Pd nanoparticle incorporated HKUST-1, and its catalytic activity for 4-nitrophenol reduction

In this study, we synthesized Pd nanoparticles incorporated into a HKUST-1 metal–organic framework (Pd/HKUST-1) via a recently developed spray synthesis method and evaluated their catalytic activity. Spray synthesis is a method for obtaining MOFs in a short time by MOF precursor solution spraying and subsequent heating. The synthesized Pd/HKUST-1 is characterized via transmittance electron microscopy (TEM) with energy dispersive X-ray spectrometry, inductively coupled plasma atomic emission spectrometry, X-ray diffraction, and N₂ adsorption measurements. TEM results revealed that Pd nanoparticles were well dispersed in HKUST-1. Pd/HKUST-1 with varying Pd nanoparticle concentrations were obtained by varying the number of commercial Pd nanoparticles in the HKUST-1 precursor solutions. The BET surface area of Pd/HKUST-1 was up to 1069 m²/g. The reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with NaBH₄ was performed using Pd/HKUST-1 as a catalyst. Moreover, the reaction rate of the 4-NP reduction is up to 160 s^–1 g^?1, which is the highest rate constant among the Pd/MOFs.     

GCMC simulations of dynamic structural change of Cu–organic crystals with N2 adsorption

N₂ adsorption on Cu–organic crystals [Cu(bpy)₂(BF₄)₂] (bpy?=?bipyridine) at 77?K begins suddenly at P/P ₀?=?0.1. This unique adsorption is named gate adsorption. Gate adsorption is associated with the change of crystal structure from GCMC and dynamic GCMC simulations. An expansion of 10% opens internal pore spaces in the crystal, giving rise to gate adsorption. The complete filling of the internal spaces with N₂ molecules induces an expansion of 30%.     

兖矿鲁化28000m~3/h空分设备流程和配置的选择

根据生产实际确定气体产品的技术参数,并结合国内外空分技术水平,选择新建设的28000m3/h空分设备的流程,详细介绍了精馏塔系统和换热器系统等静止设备和空压机、液体泵等运转设备的选型经验。     

Metal-organic framework derived hexagonal layered cobalt oxides with {1 1 2} facets and rich oxygen vacancies: High efficiency catalysts for total oxidation of propane

A cobalt-based metal–organic framework was used as a precursor to synthesize Co₃O₄ catalysts exhibiting a hexagonal layered morphology by calcination at varying temperatures. Various characterization techniques, such as XRD, SEM, Raman, H₂-TPR, O₂-TPD and N₂ adsorption–desorption, were used to study the effects of calcination temperature on the grain size, surface area, and pore volume of the catalysts. The Co₃O₄ catalyst obtained by calcination at 350 °C (Co₃O₄-350) exhibited the highest catalytic activity for the total oxidation of propane. Furthermore, the small grain size and layered structure of Co₃O₄-350 allowed it to possess a high specific surface area, a highly exposed {1 1 2} facets, and abundant oxygen defects that facilitated a favorable low-temperature reducibility and oxygen mobility, thereby improving catalytic activity. This research offers a simple strategy for synthesis of Co₃O₄ with layered structure, highly exposed {1 1 2} facets and rich oxygen defects.     

The control of paracetamol particle size and surface morphology through crystallisation in a spray dryer

The parameters governing the crystallisation of paracetamol using various conventional techniques has been extensively studied, however the factors influencing the drug crystallisation using spray drying is not as well understood. The aim of this work was to investigate the crystallisation of an active pharmaceutical ingredient through evaporative crystallisation using a spray dryer to study the physicochemical properties of the drug and to use semi-empirical equations to gain insight into the morphology and particle size of the dried powder. Paracetamol solutions were spray dried at various inlet temperatures ranging from 60 °C to 120 °C and also from a series of inlet feed solvent compositions ranging from 50/50% v/v ethanol/water to 100% ethanol and solid-state characterisation was done. The size and morphology of the dried materials were altered with a change in spray drying parameters, with an increase in inlet temperature leading to an increase in particle Sauter mean diameter (from 3.0 to 4.4 µm) and a decrease in the particle size with an increase in ethanol concentration in the feed (from 4.6 to 4.4 µm) as a result of changes in particle density and atomised droplet size. The morphology of the dried particles consisted of agglomerates of individual crystallites bound together into larger semi-spherical agglomerates with a higher tendency for particles having crystalline ridges to form at higher ethanol concentrations of the feed.