团簇Co3FeP催化析氢

为研究非晶态合金Co-Fe-P三元体系催化析氢的性能,以团簇Co3 FeP为局域模型,利用密度泛函理论和前线轨道理论,在B3LYP/Lan12dz的量化水平下,对团簇Co3 FeP的热力学稳定性和在催化水解析氢的两步反应过程中的催化性能进行分析.结果发现三重态构型能量较低且三角双锥-构型1(3)的能量最低,三角双锥-构...     

团簇Fe4P异构化反应的理论研究

采用B3LYP泛函以及程序内置的LANL2DZ基组并结合拓扑学原理,运用Gaussian 09程序对团簇Fe4 P的16种初始构型进行优化,得到8种优化构型.依据过渡态理论,从化学热力学和动力学方面对团簇Fe4 P的异构化反应进行研究,结果表明:二重态构型的稳定性最大且自旋多重度会影响团簇Fe4 P异构化转化的反应程度...     

团簇CrPS4催化性质研究

为了探究团簇CrPS₄的催化反应活性,研究其在催化方面的潜能,本文根据拓扑学原理,利用密度泛函理论,采用B3LYP泛函和def2-tzvp基组,分析了该团簇16种稳定构型的贡献率、费米能级、能隙差、态密度等方面的数据,得出以下结论：在这16种构型中,构型5^（2）的能隙差最小,电子最容易发生跃迁。构型5^（2）和构型4^（2）的催化反应活性较强,值得深入研究。团簇CrPS₄失电子能力要略强于得电子能力,S对HOMO-LUMO轨道的贡献率最大,分别为66.98%和63.93%,Cr、P原子次之,S为此团簇潜在的反应活性位点。本文丰富了团簇CrPS₄在催化方面的研究内容,为以后的应用提供了理论基础。     

Au4团簇上甲酸分解反应机理的理论研究

采用密度泛函理论方法对Au4团簇上甲酸分解反应的反应机理进行了研究,并考察了Au4团簇的两个催化活性位点。在路径Ⅰ和路径Ⅱ中,HCOOH分解的产物是CO2和H2。在路径Ⅲ和路径Ⅳ中,HCOOH分解的最终产物为CO和H2O。此外,本文研究了CO2、H2和CO、H2O两种产物的相互转化,即路径Ⅴ和路径Ⅵ。研究结果表明,路径Ⅰ和路径Ⅱ的活化自由能垒较低,即在Au4团簇上HCOOH更易分解得到CO2和H2,此外两种产物之间不容易转化。进一步研究发现团簇的大小及CeO2载体对HCOOH分解脱氢路径的活化自由能垒有一定的影响。     

Al8P8团簇环状结构与性质的密度泛函理论研究

用密度泛函理论(DFT)中的杂化密度泛函B3LYP方法, 在6-31G*水平上对Al8P8团簇的环状结构进行了几何结构优化, 并在同一水平上计算了Al8P8团簇的电子结构、振动特性及极化率和超极化率. 用自然键轨道(NBO)方法分析了成键性质, Al8P8团簇中离子键和共价键共存, 而且在不同轨道中原子间成键有不同的杂化方式. 计算结果表明: 优化后的Al8P8团簇为双层环状结构; 价电子态密度显示其电子结构具有半导体的性质; 最强的IR和Raman谱峰分别位于530.65 cm-1和366. 54 cm-1处.     

团簇Ti4 P的反应活性研究

为了得到团簇Ti4P参与化学反应时反应活性最好的结构模型,对团簇Ti4P分析时依据密度泛函理论,并在B3LYP和BP86杂化泛函和Lan12dz赝势基组分别进行分析研究.首先从能量角度分析团簇Ti4P的稳定性,得到构型1(4)即四重态构型中能量最低的戴帽三角锥构型稳定性最好,3(2)即二重态构型中能量最高的戴帽三角锥构...     

Au_n团簇催化水煤气变换反应机理的密度泛函理论研究

利用密度泛函理论(DFT)研究了Au10、Au13和Au20三类团簇的稳定性和对水煤气变换(WGSR)反应的催化活性,考察了各物质在Aun团簇上的吸附行为和微观反应机理。结果表明,三类Aun团簇的稳定性顺序为Au10Au13Au20,而Aun团簇中电子离域性及吸附能力大小趋势为Au13Au10Au20。在三类Aun团簇上,水煤气变换反应的控速步骤均为H2O的解离,但其反应机理路径有所不同。Au10团簇上为羧基机理,COOH*中间体直接解离;Au13团簇上为氧化还原机理,两个OH*发生歧化反应;Au20团簇上为羧基机理,COOH*和OH*发生歧化反应。通过对三类团簇上的最佳反应路径进行比较发现,Au13团簇在低温下具有较好的催化活性。     

单分散Ni簇锚定在CN上用于高效光催化析氢

利用太阳光在常温常压下驱动光催化反应高效进行是解决人类面临的能源、环境问题从而实现绿色化学的理想方案之一.然而,兼顾效率、成本和稳定性的高性能光催化体系的研究依然存在巨大的挑战.石墨氮化碳(g-C3N4)基光催化剂由于高稳定性、无毒无害和适合的能带结构,在光催化制氢方面存在巨大潜力.然而,表面的慢反应速率导致了光生电子...     

基于MX_4结构的配位化合物析氢反应催化性能

具有MX4结构的(M=Fe,Co,Ni,Cu等,X=N,S,Se等)小分子配位化合物及配位聚合物(MX4催化剂),由于其新颖的结构和优异的电催化析氢性能受到研究人员越来越多的关注。本文综述了MX4催化剂的研究进展,其中MX4催化剂活性受金属中心、配位原子、配体的结构以及材料的形貌、尺寸等因素的影响。理论计算有助于分析催化剂中这些因素对催化剂活性的影响,也有助于通过理论模拟,设计更合理的催化剂分子结构。     

第一性原理模拟氢气分子在氧化硅团簇上的吸附

基于密度泛函理论,采用广义梯度近似(GGA)分析了H2分子吸附在氧化硅团簇上的几何结构、电子性质以及吸附能.结果发现:H2分子与Si3O4团簇相互作用时,H2分子被分解,游离的H原子优先吸附在末端Si原子上,表明Si3O4团簇体系对氢气的存储主要依赖于末端存在悬挂键的Si原子,接着H2分子才以分子的形式以较小吸附能吸附在Si3O4H4团簇上.氢气分子主要引起与其邻近的原子电荷的重新分布.该团簇体系的红外、拉曼光谱图有效地鉴定了H2分子的吸附状态,为理论上确定团簇的稳定结构和实验上对观测结果的分析提供有力的途径.     

Quantum Chemical Study on Geometry and Property of Cluster Ni_4P

1INTRODUCTION Amorphous alloys attractive to scientists have worked in the field of materials and catalysts since they have many excellent physical and chemical pro-perties,such as high magnetic susceptibility,high specific heat,high strength,ductile in compression,low coefficient of friction,high corrosion resistance,super plasticity within the range,ferromagnetism and super conductivity[1~5].Especially,amorphous alloys as catalytic materials have shown either hig-her activity or selectiv…     

CeO2 Particles Anchored to Ni2P Nanoplate for Efficient Photo-catalytic Hydrogen Evolution

Photocatalytic hydrogen evolution can convert intermittent and dispersive solar energy into hydrogen with high energy density,which is expected to fundamentally solve the problems of environmental pollution and energy shortages.In this experiment,the performance of the catalyst is modified by introducing cocatalyst and morphology control.Ni(OH)2 nanoflowers are used as substrates to derive nanoplate stack Ni₂P by high-temperature phosphating method,and a great many of CeO₂ nanoparticles are anchored in the Ni₂P.This unique 3D/0D combination effectively inhibits the agglomeration of CeO₂ nanoparticles and shortens the electron transfer path.Secondly,the introduction of metal-like performance of Ni₂P broadens the light absorption range of the catalyst and reduces the overpotential of the catalyst,which is a key factor in enhancing the catalytic activity.The design ideas of this experiment have reference significance for the design of efficient and environmentally friendly photocatalysts.     

(Ni-Co)-WC复合电极的析氢催化性能

采用 复合电沉 积方法获 得了（ Ｎｉ Ｃｏ） Ｗ Ｃ 复合电极 ,考 察了 复合 电极 在弱 酸性、碱性 和中性介质 中的析 氢电催化 性能,并 在弱酸性 介质中 进行了电 化学稳定 性实验 ． 结果 表明,复 合电极具有优越 的析氢 电催化性 能和良好 的电化 学稳定性 ．     

p型单晶硅上电镀纳米Ni-W-P合金电极及其光照析氢研究

半导体;纳米晶;催化析氢;p型单晶硅上电镀纳米Ni-W-P合金电极及其光照析氢研究     

非贵金属助剂Ni2P修饰类石墨碳氮化物光催化剂增强可见光光催化产氢性能

Energy crisis has become a serious global issue due to the increasing depletion of fossil fuels; therefore, it is crucial to develop environmentally friendly and renewable energy resources, such as hydrogen (H₂), to replace fossil fuels. From this viewpoint, photocatalytic H₂ production is considered as one of the most promising technologies. Noble metal platinum (Pt) can be applied as an efficient cocatalyst for improving the H₂ production performance of photocatalytic systems; however, its high cost limits its further application. Thus, the development of novel, high-activity, and low-cost cocatalysts for replacing noble metal cocatalysts is of great significance for use in photocatalytic H₂ evolution techniques. Herein, we successfully synthesized a Ni₂P/graphite-like carbonitride photocatalyst (Ni₂P/CN) using a conjugated polymer (SCN)_n as precursor for enhanced photocatalytic H₂ production under visible light illumination. Various characterization techniques, including optical and photoelectronic chemical tests, were used to investigate the structural composition, morphology, and light adsorption ability of these materials. X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy results showed that Ni₂P/CN nanocomposites with good crystal structure were obtained. Scanning electron microscopy and transmission electron microscopy results revealed that the Ni₂P/CN samples had a typical two-dimensional layered structure, and the Ni₂P nanoparticles were uniformly loaded on the surface of the CN to form a non-noble metal promoter. UV-Vis diffuse reflectance spectra results demonstrated that the loading of Ni₂P nanoparticles effectively enhances the adsorption capacity of CN to visible light. Photoluminescence spectroscopy and photocurrent (PL) results suggested that Ni₂P loading to CN is beneficial for promoting the migration and separation efficiency of photogenerated carriers. Photocatalytic H₂ production was conducted under visible light irradiation with triethanolamine as a sacrificial agent. The results suggest that the Ni₂P/CN composite photocatalysts exhibit excellent photocatalytic reduction performance. In particular, the H₂ evolution rate of the optimal Ni₂P/CN nanocomposite is 623.77 μmol·h^-1·g^-1, which is higher than that of CN modified by noble metal Pt, i.e., 524.63 μmol·h^-1·g^-1. In conclusion, Ni₂P nanoparticles are homogeneously attached to the surface of CN, and a strong interfacial effect exists between them, thereby forming an electron transfer tunnel that greatly inhibits the recombination of photoinduced carriers and promotes the migration of electrons from CN to Ni₂P. In addition, a possible photocatalytic mechanism is proposed based on the experiments and characterizations. This work has profound significance for developing non-noble metal cocatalysts for the substitution of noble metal cocatalysts for high-efficiency photocatalytic H₂ evolution.      

The Influence of Elastic Strain on Catalytic Activity in the Hydrogen Evolution Reaction

Understanding the role of elastic strain in modifying catalytic reaction rates is crucial for catalyst design, but experimentally, this effect is often coupled with a ligand effect. To isolate the strain effect, we have investigated the influence of externally applied elastic strain on the catalytic activity of metal films in the hydrogen evolution reaction (HER). We show that elastic strain tunes the catalytic activity in a controlled and predictable way. Both theory and experiment show strain controls reactivity in a controlled manner consistent with the qualitative predictions of the HER volcano plot and the d‐band theory: Ni and Pt's activities were accelerated by compression, while Cu's activity was accelerated by tension. By isolating the elastic strain effect from the ligand effect, this study provides a greater insight into the role of elastic strain in controlling electrocatalytic activity.     

Ni/AC电催化剂在中性溶液中的析氢电催化性能

The Ni/active carbon (AC) electro-catalyst was prepared by chemical reduction method using coconut carbon as the support. Morphologies and structures of Ni/AC were measured and characterized by X-ray diffraction and scanning electron microscopy. The activity of the Ni/AC membrane electrodes were studied in the neutral electrolyte using Tafel polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the average size of nickel particles on the active carbon were in nano-size range. The exchange current density of hydrogen evolution reaction (HER) of Ni/AC electro-catalysts was seventy-five times more than pure nickel, so Ni/AC electro-catalysts had better electro-catalytic activity. In 1 mol·L^-1 NaCl electrolyte, the Tafelian behavior′s hydrogen evolution reaction (HER) of Ni/AC electro-catalyst at high over-potential existed in two Tefal regions. These two regions were named as “regionⅠ:0.318～0.456 V” and “regionⅡ: 0.120～0.288 V”. The rate step of regionⅠ was electron transference step. The rate step of region Ⅱ was concentration polarization.