An Approach to Preparing Ni–P with Different Phases for Use as Supercapacitor Electrode Materials

Herein, we describe a simple two‐step approach to prepare nickel phosphide with different phases, such as Ni₂P and Ni₅P₄, to explain the influence of material microstructure and electrical conductivity on electrochemical performance. In this approach, we first prepared a Ni–P precursor through a ball milling process, then controlled the synthesis of either Ni₂P or Ni₅P₄ by the annealing method. The as‐prepared Ni₂P and Ni₅P₄ are investigated as supercapacitor electrode materials for potential energy storage applications. The Ni₂P exhibits a high specific capacitance of 843.25 F g^?1, whereas the specific capacitance of Ni₅P₄ is 801.5 F g^?1. Ni₂P possesses better cycle stability and rate capability than Ni₅P₄. In addition, the Fe₂O₃//Ni₂P supercapacitor displays a high energy density of 35.5 Wh kg^?1 at a power density of 400 W kg^?1 and long cycle stability with a specific capacitance retention rate of 96 % after 1000 cycles, whereas the Fe₂O₃//Ni₅P₄ supercapacitor exhibits a high energy density of 29.8 Wh kg^?1 at a power density of 400 W kg^?1 and a specific capacitance retention rate of 86 % after 1000 cycles.     

Normal‐to‐Abnormal NHC Rearrangement of AlIII,GaIII, and InIII Trialkyl Complexes: Scope,Mechanism, Reactivity Studies,and H2 Activation

The present contribution reports experimental and theoretical mechanistic investigations on a normal‐to‐abnormal (C2‐to‐C4‐bonded) NHC rearrangement processes occurring with bulky group 13 metal NHC adducts, including the scope of such a reactivity for Al compounds. The sterically congested adducts (nItBu)MMe₃ (nItBu=1,3‐di‐tert‐butylimidazol‐2‐ylidene; M=Al, Ga, In; 1 a – c ) readily rearrange to quantitatively afford the corresponding C4‐bonded complexes (aItBu)MMe₃ ( 4 a – c ), a reaction that may be promoted by THF. Thorough experimental data and DFT calculations were performed on the nNHC‐to‐aNHC process converting the Al‐nNHC ( 1 a ) to its aNHC analogue 4 a . A nItBu/aItBu isomerization is proposed to account for the formation of the thermodynamic product 4 a through reaction of transient aItBu with THF–AlMe₃. The reaction of benzophenone with (nItBu)AlMe₃ afforded the zwitterionic species (aItBu)(CPh₂‐O‐AlMe₃) ( 6 ), reflecting the unusual reactivity that such bulky adducts may display. Interestingly, the nItBu/Al(iBu)₃ Lewis pair behaves like a frustrated Lewis pair (FLP) since it readily reacts with H₂ under mild conditions. This may open the way to future reactivity developments involving commonly used trialkylaluminum precursors.     

Ga2O3对Pt/WO3/ZrO2催化剂上正庚烷异构化反应的促进作用

考察了Ga2O3掺杂的Pt/WO3/ZrO2(Pt/WGZ)催化剂在200℃时正庚烷临氢异构化反应性能.结果表明,少量Ga2O3的加入能显著提高Pt/WGZ的催化活性,异构化选择性也有所增加,这是由于B酸位增加和B酸/L酸比的改变而引起的.Pt/WGZ催化剂连续反应80 h,正庚烷转化率和异构化选择性分别稳定在76%和94%.     

具有[3~4~48~4]笼状结构单元的微孔磷酸镓Ga_3P_2O_8(OH)_3(H_2O)的合成、晶体结构及表征

开放骨架结构金属磷酸盐不仅具有丰富的结构和组成多样性,而且在吸附、分离、和催化等方面具有潜在的应用前景[1￣3]。同磷酸铝一样[2,3],磷酸镓是开放骨架磷酸盐中一个重要的家族,其结构主要由交替的GaOn多面体(GaO4,GaO5及GaO6)和PO4四面体构成。目前,已有近百种磷酸镓在水热/溶剂热体系下成功的合成出来[4￣8],其中最著名的例子是具有二十员环超大孔磷酸镓Cloverite[5]。这些磷酸镓不仅具有结构上的新颖性,同时还具有丰富的组成计量比(Ga/P:1/2￣3/2)[9],它们的结构由多种次级结构单元(SBU)构成,拓扑相关性为定向设计提供了重要基…     

Thermal Non‐Oxidative Aromatization of Light Alkanes Catalyzed by Gallium Nitride

The thermal catalytic activity of GaN in non‐oxidative alkane dehydroaromatization has been discovered for the first time. The origin of the catalytic activity was studied experimentally and theoretically. Commercially available GaN powders with a wurtzite crystal structure showed superior stability and reactivity for converting light alkanes, including methane, propane, n‐butane, n‐hexane and cyclohexane into benzene at an elevated temperature with high selectivity. The catalyst is highly robust and can be used repeatedly without noticeable deactivation.     

镍磷物质的量比对负载型Ni2P/MCM-41催化剂结构及加氢脱硫性能的影响

以MCM-41为载体,采用一种简捷、温和法制备了负载型Ni₂P/MCM-41催化剂。用H₂程序升温还原(H₂-TPR)、X射线衍射(XRD)、N₂吸附比表面积测定(BET)和X射线光电子能谱(XPS)分析对催化剂进行了表征。以1%(质量分数)二苯并噻吩(DBT)的十氢萘溶液为原料,在连续固定床反应装置上,研究了初始Ni/P物质的量比对催化剂HDS活性的影响,并考察了催化剂的稳定性。结果表明,初始Ni/P物质的量比为1/2和1/3的前驱体,在390 ℃下还原时得到单一的Ni₂P相。初始Ni/P物质的量为1/2时,得到的催化剂活性最好。在反应温度340 ℃、压力3.0 MPa、氢/油体积比500、质量空速2.0 h^-1时,DBT的转化率接近100%。     

Nanostructured Ni2P as a Robust Catalyst for the Hydrolytic Dehydrogenation of Ammonia–Borane

Ammonia–borane (AB) is a promising chemical hydrogen‐storage material. However, the development of real‐time, efficient, controllable, and safe methods for hydrogen release under mild conditions is a challenge in the large‐scale use of hydrogen as a long‐term solution for future energy security. A new class of low‐cost catalytic system is presented that uses nanostructured Ni₂P as catalyst, which exhibits excellent catalytic activity and high sustainability toward hydrolysis of ammonia–borane with the initial turnover frequency of 40.4 mol_(H2) mol_(Ni2P)^?1 min^?1 under air atmosphere and at ambient temperature. This value is higher than those reported for noble‐metal‐free catalysts, and the obtained Arrhenius activation energy (E_a=44.6 kJ mol^?1) for the hydrolysis reaction is comparable to Ru‐based bimetallic catalysts. A clearly mechanistic analysis of the hydrolytic reaction of AB based on experimental results and a density functional theory calculation is presented.     

具有[344484]笼状结构单元的微孔磷酸镓Ga3P2O8(OH)3(H2O)的合成、晶体结构及表征

Open-framework metal phosphates have been the subject of intense research owing to their interesting structural chemistry and potential applications in catalysis and ion exchange. The gallium phosphate family has exhibits rich structural chemistry. A novel gallium phosphate Ga₃P₂O₈(OH)₃(H₂O)(GaPO-CJ36) has been prepared in a hydrothermal reaction system of GaO(OH)-H₃PO₄-Co(chxn)₃Cl₃-H₂O at 180 ℃ for 7 days. Single-crystal X-ray analysis shows that GaPO-CJ36 crystallizes in the P2₁/c space group with a=1.833 35(12) nm, b=0.503 94(3) nm, c=1.062 90(9) nm, V=0.982 01(12) nm³, and Z=4. The connection of GaO₂(OH)₃(H₂O) octahedra, PO₄ and GaO₄ tetrahedra through vertex oxygen atoms forms a three-dimensional open framework, which contains 8-ring channels along the [010] direction. Its structure is composed of interesting [3⁴4⁴8⁴] cages, which have not been found in known gallium phosphates. CSD: 416779.     

Ni_2P催化剂的低温还原法合成及其HDS性能

在低还原温度下程序升温还原法制备了Ni2P/MCM-41催化剂,并采用H2-TPR、TG-DTG、XRD、BET、XPS等手段对制备的催化剂进行了表征,考察了还原温度对活性相Ni2P形成以及催化剂二苯并噻吩HDS性能的影响。结果表明,在210~390℃下还原得到的催化剂活性相为单一的Ni2P相;在390℃下还原得到的催化剂具有最高的二苯并噻吩HDS活性,在反应温度340℃、反应压力3.0 MPa、氢/油体积比500、质量空速(WHSV)2.0 h-1的条件下二苯并噻吩HDS转化率达到99.0%。