反应球磨中Mg的直接氢化

采用反应球磨法使 Ｍｇ在 ＺｒＦｅ１．４Ｃｒ０．６的催化作用下直接氢化生成纳米结构的 ＭｇＨ２和ｒ－ＭｇＨ２利用 Ｘ射线衍射及热重分析对氢化相的生成进行分析和表征．在反应球磨过程中存在动态的氢化平衡．

直接氢化法制备氢化铝钠及性质

以普通铝粉、卤代烃、氢化钠和H2等为主要原料,在常压低于100℃的条件下,采用铝的格氏试剂法,成功制备出氢化铝钠Na Al H4。通过FTIR、XRD表征,结合元素分析,研究其成分及结构,表明样品为氢化铝钠,实际与理论产率比值达到90%以上;根据SEM和online MS,对其进行表面形貌和稳定性研究。结果显示,晶体结构较完整,室温下稳定性好,自身储氢量与市售样品相当。该方法实现了常压下氢化铝钠的制备,且反应在常压下进行,产率和原料利用率都达到了工业要求,对其生产工艺的改进具有促进作用。

二氧化碳还原制甲醇方法

综述了现有的几种CO2制甲醇方法,主要有直接氢化还原法、间接氢化还原法、串联氢化还原法以及电催化还原法、光催化还原法和生物催化还原法,总结了各种方法的优缺点;介绍了国内外CO2制甲醇现有的几种制备方法的最新工业进展,指出了制约国内外CO2制甲醇技术发展的关键因素;最后对CO2制甲醇的发展前景做出分析。

对—氨基苯酚合成新工艺初探

本文对近十年国内外合成对—氨基苯酚新工艺情况进行了综述,并突出了有前途的合成新工艺——以Pt/C等作为催化剂的硝基苯直接氢化法。该法收率高、三废少、成本低,是今后对—氨基苯酚工业化生产的必然发展方向。

过渡金属催化的碳氢键官能团化反应合成平面手性二茂铁化合物

在不对称催化反应中,平面手性二茂铁化合物是一类非常高效的手性配体和催化剂.从原子和步骤经济性方面考虑,与传统方法相比不对称碳氢键直接官能团化反应是构建平面手性二茂铁最简洁有效的方法.综述了铜、钯、铑、铱、金和铂等过渡金属催化的不对称碳氢键官能团化反应合成平面手性二茂铁化合物的最新进展.此外,还介绍了利用这些方法合成多种平面手性二茂铁配体和催化剂及其不对称催化反应.

Electronic interaction between single Pt atom and vacancies on boron nitride nanosheets and its influence on the catalytic performance in the direct dehydrogenation of propane

The electronic metal-support interaction(EMSI)is one of most intriguing phenomena in heterogeneous catalysis.In this work,this subtle effect is clearly demonstrated by density functional theory(DFT)calculations of single Pt atom supported on vacancies in a boron nitride nanosheet.Moreover,the relation between the EMSI and the performance of Pt in propane direct dehydrogenation(PDH)is investigated in detail.The charge state and partial density of states of single Pt atom show distinct features at different anchoring positions,such as boron and nitrogen vacancies(Bvac and Nvac,respectively).Single Pt atom become positively and negatively charged on Bvac and Nvac,respectively.Therefore,the electronic structure of Pt can be adjusted by rational deposition on the support.Moreover,Pt atoms in different charge states have been shown to have different catalytic abilities in PDH.The DFT calculations reveal that Pt atoms on Bvac(Pt-Bvac)have much higher reactivity towards reactant/product adsorption and C–H bond activation than Pt supported on Nvac(Pt-Nvac),with larger adsorption energy and lower barrier along the reaction pathway.However,the high reactivity of Pt-Bvac also hinders propene desorption,which could lead to unwanted deep dehydrogenation.Therefore,the results obtained herein suggest that a balanced reactivity for C–H activation in propane and propene desorption is required to achieve optimum yields.Based on this descriptor,a single Pt atom on a nitrogen vacancy is considered an effective catalyst for PDH.Furthermore,the deep dehydrogenation of the formed propene is significantly suppressed,owing to the large barrier on Pt-Nvac.The current work demonstrates that the catalytic properties of supported single Pt atoms can be tuned by rationally depositing them on a boron nitride nanosheet and highlights the great potential of single-atom catalysis in the PDH reaction.

Promotional effects of Sb on Pd-based catalysts for the direct synthesis of hydrogen peroxide at ambient pressure

TiO2‐supported Pd‐Sb bimetallic catalysts were prepared and evaluated for the direct synthesis of H2O2 at ambient pressure.The addition of Sb to Pd significantly enhanced catalytic performance,and a Pd50Sb catalyst showed the greatest selectivity of up to 73%.Sb promoted the dispersion of Pd on TiO2,as evidenced by transmission electron microscopy and X‐ray diffraction.X‐ray photoelectron spectroscopy indicated that the oxidation of Pd was suppressed by Sb.In addition,Sb2O3 layers were formed and partially wrapped the surfaces of Pd catalysts,thus suppressing the activation of H2 and subsequent hydrogenation of H2O2.In situ diffuse reflection infrared Fourier transform spectroscopy for CO adsorption suggested that Sb homogenously located on the surface of Pd‐Sb catalysts and isolated contiguous Pd sites,resulting in the rise of the ratio of Pd monomer sites that are favorable for H2O2 formation.As a result,the Sb modified Pd surfaces significantly enhanced the non‐dissociative activation of O2 and H2O2 selectivity.

A direct electrochemical route from oxides to TiMn_2 hydrogen storage alloy

This study is for investigating the direct electro-deoxidation of mixed TiO2-Mn02 powder to prepare TiMn2 alloy in molten calcium chloride. The influences of process parameters, such as sintering temperature, cell voltage, and electrolysis time, on the electrolysis process were examined to investigate the mechanism of alloy formation. The composition and morphology of the products were analyzed by XRD and SEM, respectively. The electrochemical property of TiMn2 alloy was investigated by cyclic voltammetry measurements. The results show that pure TiMn2 can be prepared by direct electrochemical reduction of mixed TiO2/Mn02 pellets at a voltage of 3.1 V in molten calcium chloride of 900 ℃ for 7 h. The electro-deoxidation proceeds from the reduction of manganese oxides to Mn, which is reduced by Ti02 or CaTiOB to form TiMn2 alloy. The cyclic voltammetry measurements using pow- der microelectTode show that the prepared TiMn2 alloy has good electrochemical hydrogen storage property.

The DDA-II Process for Manufacture of Diesel Fuel Meeting the Euro-IV or even Higher Emission Standard

The DDA-Ⅱ process aimed at manufacture of diesel fuel meeting the Euro-Ⅳ emission standard from inferior diesel feedstock has been developed and tested in pilot scale. This technology adopts non-noble metal catalysts and a highly integrated two-stage process scheme featuring low investment and operating cost and convenience in operation. Under an appropriate process regime the DDA-Ⅱ technology can process FCC LCO, a blend of straight-run diesel and FCC LCO, or the SR diesel to yield the diesel product streams meeting the Euro-Ⅳ or even higher emission standards.

Direct synthesis of parallel doped N-MoP/N-CNT as highly active hydrogen evolution reaction catalyst

Doped phosphide is promising in earthabundant element based catalysts for hydrogen evolution reaction(HER). Here we employ ammonium hypophosphite(NH4H2PO2) to synthesize a novel parallel doped catalyst,nitrogen doped molybdenum phosphide nanoparticles(NPs)supported on nitrogen doped carbon nanotubes(N-MoP/N-CNTs). The NH4H2PO2 as a bifunctional agent severs as both phosphidation agent and nitrogen source, which makes the synthetic route simple and efficient. The as-obtained parallel doped N-MoP/N-CNTs show an overpotential of 103±5 mV at 10 mA cm-2, which is 140 mV lower than that of MoP NPs. The enhanced HER performance is attributed to the electronic effect by doped MoP and CNTs supports. This work provides a facile route to synthesize doped phosphides for the potential applications in hydrogen energy.