关于常见元素的氢化物的研究

根据氢原子结构的性质综述了常见元素的氢化物的化学键特征，氢化物的类别及其性质。

Hydrogenation reaction characteristics and properties of its hydrides for magnetic regenerative material HoCu_2

The hydrogenation reaction characteristics and the properties of its hydrides for the magnetic regenerative material HoCu_2(CeCu_2-type) of a cryocooler were investigated. The XRD testing reveals that the hydrides of HoCu_2 were a mixture of Cu, unknown hydride Ⅰ, and unknown hydride Ⅱ. Based on the PCT(pressure-concentration-temperature) curves under different reaction temperatures, the relationships among reaction temperature, equilibrium pressure, and maximum hydrogen absorption capacity were analyzed and discussed. The enthalpy change ΔH and entropy change ΔS as a result of the whole hydrogenation process were also calculated from the PCT curves. The magnetization and volumetric specific heat capacity of the hydride were also measured by SQUID magnetometer and PPMS, respectively.

pH-Induced selective electrocatalytic hydrogenation of furfural on Cu electrodes

The efficient and selective electrocatalytic hydrogenation(ECH)of furfural is considered a green strategy for achieving biomass-derived high-value chemicals.Regulating an aqueous electrolytic environment,a green hydrogen energy source of water,is significant for improving the selectivity of products and reducing energy consumption.In this study,we systematically investigated the mechanism of pH dependence of product selectivity in the ECH of furfural on Cu electrodes.Under acidic conditions,the oxygen atom dissociated directly from hydrogenated furfural-derived alkoxyl intermediates,followed by stepwise hydrogenation until H_(2)O formation via a thermodynamically favorable proton-coupled electron transfer process,thereby inducing a high proportion of the hydrogenolysis product(2-methylfuran).However,under partial alkaline conditions,furfural could be directly hydrogenated to furfuryl alcohol(selectivity~98%)due to the high-energy barrier of the deoxidation process via a surface hydride(Had)transfer.Our results highlight the vital role of the electrolytic environment in furfural selective conversion and broaden our fundamental understanding of hydrodeoxygenation reactions in ECH.

Selective propylene epoxidation in liquid phase using highly dispersed Nb catalysts incorporated in mesoporous silicates

Selective propylene epoxidation to propylene oxide(PO) with hydrogen peroxide(H_2O_2) was carried out in a catalytic semi-batch reactor.High propylene epoxidation activity(44 h^(-1)) was observed over Nb based mesoporous silicate materials Nb-TUD-1 under mild operating conditions.The physical and chemical properties of the Nb based silicates characterized using BET,FTIR,TPD,TEM and UV–Vis revealed that the site isolation and surface acidity are crucial for PO production.Catalyst synthesis methods were investigated for their effects on PO productivity,PO selectivity and H_2O_2 utilization efficiency.It is found that Nb-TUD-1 material synthesized by the sol–gel method is more active and selective than impregnated materials for liquid phase propylene epoxidation.Surface characterization confirms that thus synthesized Nb-TUD-1 catalysts have more Lewis acidity and less Bronsted acidity compared to the catalysts by impregnation.

Co-intensification of gold leaching with heavy metals and hydrogen peroxide

Co-intensification was researched to accelerate gold leaching with regards to its electrochemical nature by using anodic intensifiers of heavy metal ions (Pb2+,Bi3+,Tl+,Hg2+ and Ag+) on the basis of hydrogen peroxide assistant leaching on three different types of materials which were classified as a refractory sulphide gold concentrate,an easily leachable sulphide gold concentrate,and a low grade oxide gold ore according to their leaching characteristics.The results showed that,favorable co-intensification effects on the three materials were obtained and leaching time of gold was effectively shortened to no longer than 12 h from 16 to 24 h for hydrogen peroxide assistant leaching.For the five tested heavy metal ions,Bi3+and Tl+ presented co-intensifying effect on all the three materials,and Hg2+ caused co-intensifying effect on both refractory and easily leachable sulphide gold concentrates,and Pb2+ and Ag+ only had co-intensifying effect on the easily leachable sulphide gold concentrate.

Measurement and correlation of physical properties of aqueous solutions of tetrabutylammonium hydroxide, piperazine and their aqueous blends

The density,viscosity and refractive index of aqueous solutions of tetrabutylammonium hydroxide(TBAOH),piperazine(PZ) and their aqueous blends are determined at several temperatures(303.15 to 333.15 K).All these measured physicochemical properties decreases with an increase in temperature.The density data is used to calculate the coefficient of thermal expansion and excess molar volume of all aqueous binary and ternary solutions.The coefficient of thermal expansion increases with increase in temperatures and concentrations.The negativity of excess molar volume for all the aqueous solution decreased with increase in temperature.Each physical property is correlated with temperature by least square method and the corresponding coefficients for each property are presented.The prediction values from correlations for the physical properties are in good agreement with the experimental values.

Practice and design of the self-purification system for heavy metals-bearing contaminants

Many minerals in nature have self-purification capacity to hold and stabilize deleterious contaminants into their lattice structures,which can be used for treatment of heavy metals-bearing contaminants. Hydrotalcite Layer Double Hydroxide (LDH),tobermorite Calcium Silicate Hydrate (CSH) and apatite are ubiquitous minerals in nature,having higher geochemical stability and potential for binding and stabilizing heavy metals. Based on the elucidation of crystal structure property and self-purification principles of the three minerals above,this article discussed how to design the self-purification system of heavy metal-bearing contaminants.

Carbonaceous aerogel and CoNiAl-LDH@CA nanocomposites derived from biomass for high performance pseudo-supercapacitor

Conversion of waste biomass to valuable carbonaceous material is a sustainable and environmental benign method for energy and reduction of greenhouse gas emission. Herein, a two-step hydrothermal method was developed to fabricate high performance electrode material from pomelo peels. In the first step, the pomelo peels were transformed to carbonaceous aerogel （CA）, which constructed of three- dimensional, sponge-like brown monolith with hierarchical pores, low-density （0.032 g]cm3） and excel- lent mechanical flexibility. Then, the cobalt nickel aluminum layered double hydroxide （CoNiAI-LDH） was in situ loaded on the surface of CA to form exquisite core-shell structure （CoNiAI-LDH@CA） through the second hydrothermal step. When used as an electrode material for supercapacitor, CoNiA1-LDHOCA exhibited high specific capacitances of 1,134F/g at 1A/g and 902Fig at 10A/g, respectively. Furthermore, they displayed an excellent cycling stability without an obvious capacitance decrease after 4,000 cycles.

Light weight, mechanically strong and biocompatible α-chitin aerogels from different aqueous alkali hydroxide/urea solutions

Light weight and mechanically strong α-chitin aerogels were fabricated using the sol-gel/self-assembly method from α-chitin in different aqueous alkali hydroxide(KOH, Na OH and Li OH)/urea solutions. All of the α-chitin solutions exhibited temperature-induced rapid gelation behavior. 13 C nuclear magnetic resonance(NMR) spectra revealed that the aqueous alkali hydroxide/urea solutions are non-derivatizing solvents for α-chitin. Fourier transform infrared(FT-IR), X-ray diffraction(XRD) and cross-polarization magic angle spinning(CP/MAS) 13 C NMR confirmed that α-chitin has a stable aggregate structure after undergoing dissolution and regeneration. Subsequently, nanostructured α-chitin aerogels were fabricated by regeneration from the chitin solutions in ethanol and then freeze-drying from t-Bu OH. These α-chitin aerogels exhibited high porosity(87% to 94%), low density(0.09 to 0.19 g/cm^3), high specific surface area(419 to 535 m^2/g) and large pore volume(2.7 to 3.8 cm^3/g). Moreover, the α-chitin aerogels exhibited good mechanical properties under compression and tension models. In vitro studies showed that m BMSCs cultured on chitin hydrogels have good biocompatibility. These nanostructured α-chitin aerogels may be useful for various applications, such as catalyst supports, carbon aerogel precursors and biomedical materials.