A mesoporous non-precious metal boride system: synthesis of mesoporous cobalt boride by strictly controlled chemical reduction

Generating high surface area mesoporous transition metal boride is interesting because the incorporation of boron atoms generates lattice distortions that lead to the formation of amorphous metal boride with unique properties in catalysis. Here we report the first synthesis of mesoporous cobalt boron amorphous alloy colloidal particles using a soft template-directed assembly approach. Dual reducing agents are used to precisely control the chemical reduction process of mesoporous cobalt boron nanospheres. The Earth-abundance of cobalt boride combined with the high surface area and mesoporous nanoarchitecture enables solar-energy efficient photothermal conversion of CO₂ into CO compared to non-porous cobalt boron alloys and commercial cobalt catalysts.

Generating high surface area mesoporous transition metal boride is challenging but interesting because incorporation of boron atoms can generate lattice distortion to form amorphous metal boride which has unique properties in catalysis.     

分子筛USY负载硼化钴非晶态合金催化剂的制备及其在催化硼氢化钠水解制氢中的应用

采用浸渍法与化学还原法相结合制备了一系列USY型分子筛负载非晶态合金硼化钴(CoB/USY)催化剂,并系统探究了该催化剂在催化硼氢化钠水解制氢中的催化活性。 XRD表征表明,USY分子筛载体上负载的活性组分CoB属于非晶态结构。 通过扫描电子显微镜,对比了负载型CoB/USY催化剂和粉末状CoB催化剂的微观形貌,发现非晶态合金活性组分CoB能够很好的分布在USY分子筛载体表面,较粉末状CoB有更高的分散度。 催化硼氢化钠水解制氢实验结果表明,相对于粉末状CoB催化剂,负载型CoB/USY催化剂在硼氢化钠水解制氢中具有更高的催化活性,30 ℃时NaBH₄水解产氢速率约为1.5 L/(min·g)。 反应动力学的计算结果显示,负载型CoB/USY催化剂在催化NaBH₄水解制氢反应中表观活化能约为65.9 kJ/mol,大大低于粉末状CoB催化剂的活化能(72.1 kJ/mol)。     

Boron: A key functional component for designing high-performance heterogeneous catalysts

Heterogeneous catalysis is a vivid branch of traditional catalysis field, with the advantage of high efficiency and being easily separated from reactants and products after reaction, and have received widespread attentions in large-scale industrial production, especially in the field of energy utilization. Boron has been found to be a key functional component for designing high-performance heterogeneous catalysts. In this review, we cover and categorize the past and recent progress in boron-containing materials and their applications in heterogeneous catalysis particularly in energy‐related fields. The fundamental roles of boron components in the emerging heterogeneous catalysis of construction, regulation and stabilization of active phases/sites are highlighted, with the emphasis on how they regulating structural and electronic properties of host materials. We then categorize boron-containing catalysts into six kinds mainly including intermetallic boride catalysts, metal boride-derived catalysts, boron-doped catalysts, metal boride-decorated catalysts, boron-containing compounds as catalyst supports, and single-boron-site catalysts, as well as try to establish structure-catalytic activity relationship. The catalytic applications of these six boron-containing catalysts are discussed separately, focusing on the energy-related reactions such as hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO₂RR) and nitrogen reduction reaction (NRR). Finally, the opportunities and challenges related to boron-containing compounds in the field of catalysis are prospected.     

Vergleichende Untersuchungen zur katalytischen Aktivität von Nickel und kristallinen Nickelboriden sowie RANEY-Nickel und borhaltigem RANEY-Nickel: Hydrierungs- und Dehydrierungsreaktionen,elektrochemische Methanoloxydation

The catalytic activation of the decomposition of gaseous formic acid with nickel powder and crystalline nickel borides is compared. Only after treatment with NH₃-solution the activity of the nickel borides has the same order as that of nickel powder. Ni₃B is the best of the catalysts used. The crystalline nickel borides cannot catalyze the anodic oxydation of methanol in alcaline solution at 80°C. — Nickel catalysts containing Boron can be prepared by the RANEY method from nickel boride and aluminum. These catalysts have the same activity as normal RANEY nickel with respect to the hydrogenation of the C?C? bond in crotonic acid; they are more active with respect to the C?O? bond of acetone. Methanol can be oxydised fastly in alcaline solution at 80°C on electrodes containing RANEY nickel. RANEY nickel containing boron is still better.     

Nickel Boride Catalyst in Organic Synthesis—The Effects of Promoters on Nickel Borides for Hydrogenation Reactions

Cr, Co and Rh were introduced into P-1, P-2 and P-2W nickel boride catalysts as promoters. The substrates of cyclohexanone and cyclohexene were used to examine the effects of those promoters on nickel borides for hydrogenation reactions. On cyclohexanone with strongly-polared carbonyl group, Cr, Co and Rh are effective for all nickel borides. On cyclohexene with slightly-polared olefinic group, Rh is also good for all nickel borides. But Cr and Co are only effective for P-2W and P-1 nickel borides respectively.     

Tailoring WB morphology enables d-band centers to be highly active for high-performance lithium-sulfur battery

The d-band centers of catalysts have exhibited excellent performance in various reactions. Among them, the enhanced catalytic reaction is considered a crucial way to power dynamics and reduce the “shuttle” effect in polysulfide conversions of lithium-sulfur batteries. Here, we report two-dimensional-shaped tungsten borides (WB) nanosheets with d-band centers, where the d orbits of W atoms on the (001) facets show greatly promoting the electrocatalytic sulfur reduction reaction. As-prepared WB-based Li-S cells exhibit excellent electrochemical performance for Li-ion storage. Especially, it delivers superior capacities of 7.7 mAh/cm² under the 8.0 mg/cm² sulfur loading, which is far superior to most other electrode catalysts. This study provides insights into the d-band centers as a promising catalyst of two-dimensional boride materials     

Magnesium boride sintered as high-energy fuel

Boron was chosen as fuel owing to its excellent thermodynamic values for combustion. The difficulty of the boron in combustion is the formation of a surface oxide layer, which postpones the combustion process, reducing the performance of the rocket engine. In this paper, magnesium boride was sintered as high-energy fuel as a substitute for boron. The combustion heat and efficiency of magnesium boride and boron were determined using oxygen bomb calorimeter. The combustion characteristics of magnesium boride were investigated by thermal analysis, chemical analysis, XRD, and EDS. Results show that the combustion performance of magnesium boride are better than that of amorphous boron in oxygenated environments. The evaporation of magnesium in magnesium boride combustion process prevent the formation of a closed oxide layer, leading to higher combustion efficiency.     

Total Synthesis of Callyspongiolide,Part 2: The Ynoate Metathesis/cis-Reduction Strategy

The macrocyclic core of the cytotoxic marine natural product callyspongiolide ( 1 ) was forged by ring-closing alkyne metathesis (RCAM) of an ynoate precursor using a molybdenum alkylidyne complex endowed with triarylsilanolate ligands as the catalyst. This result is remarkable in view of the failed attempts documented in the literature at converting electron deficient alkynes with the aid of more classical catalysts. The subsequent Z-selective semi-reduction of the resulting cycloalkyne by hydrogenation over nickel boride required careful optimization in order to minimize overreduction and competing dehalogenation of the compound's alkenyl iodide terminus as needed for final attachment of the side chain of 1 by Sonogashira coupling. The required cyclization precursor itself was prepared via Kocienski olefination.     

Thermodynamics of oxidation of zirconium and hafnium borides

Gibbs thermodynamic potentials of oxidation of zirconium and hafnium diborides with molecular and atomic oxygen and nitrogen monoxide were calculated for a temperature range of 20–2500°C. Oxidation of zirconium and hafnium borides with atomic oxygen was found to be the most expected reaction. The probability of oxidation is lower for zirconium boride than that for hafnium boride.     

Heat capacity and characteristic thermodynamic functions of dysprosium boride DyB62 in the temperature range of 2 to 300 K

Heat capacity at constant pressure C _p (T) of a dysprosium boride DyB₆₂ single crystal obtained by zone melting was studied experimentally in the temperature range of 2 to 300 K. Abnormally high values of dysprosium boride heat capacity were revealed in the range of 2–20 K, due to the magnetic contribution and the effect of disorder in the boride lattice. Temperature changes in DyB₆₂ enthalpy, entropy, Gibbs energy, and standard values of these thermodynamic functions were calculated.     

Synthesis of (±)-cis-tetradec-5-en-4-olide — The racemate of the sex pheromone of the Japanese beetle

A three-stage method has been developed for the stereoselective synthesis of (±)-cis-tetradec-5-en-4-olide — the racemate of the sex pheromone of the Japanese beetlePopillia japonica C. The key reactions used were the stereoselective cis reduction of a triple bond with the aid of heterogeneous hydrogenation catalysts (zinc-copper couple, nickel boride, Lindlar catalyst) and the radical lactonization of conjugated systems by the action of acetic acid in the presence of manganese acetate.Institute of Organic Chemistry, Academy of Sciences of the Armenian SSR, Erevan. All-Union Scientific-Research Institute of Chemical Agents for Plant Protection. Tartu State University. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 98–102, January–February, 1984.     

Element-selective atomic emission detection for capillary GC of metal-containing compounds

Element-selective GC detection by microwave-induced plasma atomic emission spectroscopy has been used to examine a wide variety of compounds containing metals, non-metals, and metalloids. “Recipes”, or new selective detection schemes for use with the software of the computer-controlled system, have been developed for the selective detection of boron, aluminum, gallium, titanium, vanadium, chromium, manganese, rhenium, palladium, and platinum. Figures of merit including limits of detection, linear dynamic range, and spectral selectivity over carbon have been established for most of these elements. Gas chromatography – atomic emission detection (GC-AED) has been applied to the selective detection of vanadium, nickel, and iron in metalloporphyrins present in crude oil, manganese-selective detection of methylcyclopentadienylmanganese tricarbonyl (MMT) in gasoline, and titanium-selective detection of reaction mixtures containing titanium catalysts or titanium boride molecular precursors.     

PREPARATION OF MONODISPERSE NICKEL (COBALT) BOR1DE CATALYST USING REVERSED MICELLAR SYSTEM

Reactions of Ni(II) or Co(II) cations with NaBH₄ are prepared for monodisperse Ni₂B or Co₂B. These materials are at first dissolved in the inner water cores of reverse micelles composed of CTAB, 1-hexanol (1-pcntanol or 1—butyl alcohol) and water, then react with NaBH4 at room temperature. The reverse micelles provide a very convenient way of producing nickel boridc (or cobalt boride) particles of predetermined size if a well defined micellar composition and the concentration of the reducing agent arc precisely controlled. The experimental results demonstrate that the type of catalysts produced arc nearly monodisperse particles and have an activity superior to that of Raney nickel )or Rancy cobalt) in hydrogenation of certain olefins.     

Investigation of composition and chemical state of elements in iron boride by the method of X-ray photoelectron spectroscopy

The composition and chemical state of iron and boron in the surface layer of iron boride under different kinds of pretreatment of samples have been investigated by the method of X-ray photo-electron spectroscopy. It has been found that in the initial sample there is oxygen chemically combined with iron and boron atoms. Upon heating (450°C) in hydrogen, in argon, and in vacuo there occurs removal of oxygen only from iron atoms (no pure iron was found to be formed). Boron oxidizes and there probably appears a new surface combination of boron with oxygen in which the bonding energy of 1s electrons is higher than that in B₂O₃. Treatment of the iron boride surface with argon ions and with protons ensures uniform removal of oxygen from iron and boron atoms. It has been found that thermal treatment of iron boride leads to depletion of iron atoms from the sample surface layer, and pickling with argon ions and with protons leads to strong enrichment. Iron boride samples subjected to Ar⁺ and H⁺ bombardment tend to undergo significant oxidation when subsequently exposed to air at room temperature.     

Development and application of high strength ternary boride base cermets

Reaction boronizing sintering is a novel strategy to form a ternary boride coexisting with a metal matrix in a cermet during liquid phase sintering. This new sintering technique has successfully developed world first ternary boride base cermets with excellent mechanical properties such as Mo₂FeB₂, Mo₂NiB₂ and WCoB base ones.In these cermets Mo₂FeB₂ and Mo₂NiB₂ base ones consist of a tetragonal M₃B₂ (M: metal)-type complex boride as a hard phase and a transition metal base matrix. The cermets have already been applied to wear resistant applications such as injection molding machine parts, can making tools, and hot copper extruding dies, etc.This paper focuses on the characteristics, effects of the additional elements on the mechanical properties and structure, and practical applications of the ternary boride base cermets.     

Cobalt, a reactive metal in releasing hydrogen from sodium borohydride by hydrolysis: A short review and a research perspective

Cobalt is commonly admitted as being a promising catalyst in accelerating NaBH₄ hydrolysis, being as reactive as noble metals and much more cost-effective. This is the topic of the present paper. Herein, we survey (i) the NaBH₄-devoted literature while especially focusing on the Co catalysts and (ii) our work on the same topic. Finally, we report (iii) reactivity results of newly developed Co-based catalysts. From both surveys, it mainly stands out that Co has been investigated as catalysts in various forms: namely, as chlorides, reduced nanoparticles (metal Co, Co boride, Co-B alloy), supported over supports and shaped. In doing so the reactivity can be easily varied achieving H₂ generation rates from few to >1000 L(H₂)/min·g (metal). Nevertheless, our work can be distinguished from the NaBH₄ literature. Indeed, we are working on strategies that focus on making alternative Co-based catalysts. One of these strategies is illustrated here as we report new reactivity data of Co-based bimetallic supported catalysts. For example, we show that 20 wt% Co⁹⁰Y¹⁰/γAl₂O₃-20 wt% Co⁹⁵Hf⁵/γAl₂O₃ > 20 wt% Co⁹⁹Zr¹/γAl₂O₃ > 20 wt% Co/γAl₂O₃, the best catalysts showing HGRs of about 245 mL(H₂)/min or 123 L(H₂)/min·g (metals).     

Importance of catalyst–photoabsorber interface design configuration on the performance of Mo-doped BiVO4 water splitting photoanodes

Photoelectrochemical water splitting is mostly impeded by the slow kinetics of the oxygen evolution reaction. The construction of photoanodes that appreciably enhance the efficiency of this process is of vital technological importance towards solar fuel synthesis. In this work, Mo-modified BiVO₄ (Mo:BiVO₄), a promising water splitting photoanode, was modified with various oxygen evolution catalysts in two distinct configurations, with the catalysts either deposited on the surface of Mo:BiVO₄ or embedded inside a Mo:BiVO₄ film. The investigated catalysts included monometallic, bimetallic, and trimetallic oxides with spinel and layered structures, and nickel boride (Ni_xB). In order to follow the influence of the incorporated catalysts and their respective properties, as well as the photoanode architecture on photoelectrochemical water oxidation, the fabricated photoanodes were characterised for their optical, morphological, and structural properties, photoelectrocatalytic activity with respect to evolved oxygen, and recombination rates of the photogenerated charge carriers. The architecture of the catalyst-modified Mo:BiVO₄ photoanode was found to play a more decisive role than the nature of the catalyst on the performance of the photoanode in photoelectrocatalytic water oxidation. Differences in the photoelectrocatalytic activity of the various catalyst-modified Mo:BiVO₄ photoanodes are attributed to the electronic structure of the materials revealed through differences in the Fermi energy levels. This work thus expands on the current knowledge towards the design of future practical photoanodes for photoelectrocatalytic water oxidation.

     

Nickel Boride Catalysts in Organic Synthesis (IV). The Effect of Water Washing on P-2 Nickel Boride Catalyst

Water washing of P-2 nickel boride brings about a new catalyst designated as P-2W nickel boride. This P-2W catalyst is more reactive than P-1 or P-2 in the hydrogenation of cyclohexanone and nitrobenzene. The P-2W, however, is less selective than P-2 in the hydrogenation of cyclic olefins.     

A novel route to nanosized molybdenum boride and carbide and/or metallic molybdenum by thermo-synthesis method from MoO3, KBH4, and CCl4

Nanosized molybdenum boride and carbide were synthesized from MoO₃, KBH₄, and CCl₄ by thermo-synthesis method at lower temperature. The relative content of Mo, Mo₂C, and molybdenum boride in the product was decided by the molar ratio between MoO₃, KBH₄, and CCl₄. Increasing the molar ratio of CCl₄ to MoO₃ was favorable to the production of Mo₂C. Increasing the molar ratio of KBH₄ to MoO₃ was favorable to the production of molybdenum boride. By carefully adjusting the reaction conditions and annealing in Ar at 900°C, a single phase of MoB could be obtained.     

Selective reduction of aldehydes in presence of a ketone with chlorotrimethylsilane and nickel boride

It has been shown that a combination of chlorotrimethylsilane and nickel boride effects the chemoselective reduction of an aldehyde in presence of a ketonic carbonyl group.