and Perspectives Sophie Carenco,†,‡,§,∥,⊥ David Portehault,*,†,‡,§ Ced́ric Boissier̀e,†,‡,§ Nicolas Meźailles, and Cleḿent Sanchez*,†,‡,§ †Chimie de la Matier̀e Condenseé de Paris, UPMC Univ Paris 06, UMR 7574, Colleg̀e de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France ‡Chimie de la Matier̀e Condenseé de Paris, CNRS, UMR 77574, Colleg̀e de France, 11 Place Marcellin Berthelot, 75231 Paris Cedex 05, France Chimie de la Matier̀e Condenseé de Paris, Colleg̀e de France, 11 Place Marcellin Berthelot, 75231 Paris Cedex 05, France Laboratory Heteroelements and Coordination, Chemistry Department, Ecole Polytechnique, CNRS-UMR 7653, Palaiseau, France

Nanoscaled metal borides and phosphides: recent developments and perspectives

Progress in design of new amorphous alloy catalysts

Chemical preparation and characterization of metal–metalloid ultrafine amorphous alloy particles

Amorphous alloys structurally deviate from crystalline materials in that they possess unique short-range ordered and long-range disordered atomic arrangement. They are important catalytic materials due to their unique chemical and structural properties including broadly adjustable composition, structural homogeneity, and high concentration of coordinatively unsaturated sites. As chemically reduced metal–metalloid amorphous alloys exhibit excellent catalytic performance in applications such as efficient chemical production, energy conversion, and environmental remediation, there is an intense surge in interest in using them as catalytic materials. This critical review summarizes the progress in the study of the metal–metalloid amorphous alloy catalysts, mainly in recent decades, with special focus on their synthetic strategies and catalytic applications in petrochemical, fine chemical, energy, and environmental relevant reactions. The review is intended to be a valuable resource to researchers interested in these exciting catalytic materials. We concluded the review with some perspectives on the challenges and opportunities about the future developments of metal–metalloid amorphous alloy catalysts.

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Synthesis and catalysis of chemically reduced metal–metalloid amorphous alloys

A series of ultafine Ni−P, Ni−B, and Ni−P−B amorphous alloy catalysts with various atomic ratios were prepared by a chemical reduction method. The catalysts were characterized with respect to elemental analysis, nitrogen sorption, XRD, TEM, XPS, and hydrogenation activity. Conventional Raney nickel was included for comparison. The Ni/P/B molar ratio in the starting material significantly affected the concentration of boron and phosphorus bonded to the nickel metal, subsequently affecting the surface area, the amorphous structure, and the hydrogenation activity and selectivity of the catalyst. The different electron transfer between nickel metal and the metalloid elements in Ni−P and Ni−B powders (phosphorus draws electrons and boron donates electrons) results in the extremely different hydrogenation activity of furfural (specific activity per surface area: Ni85.0P15.0 ≫ Ni71.4B28.9). By regulating a suitable P/B ratio, the ultrafine Ni−P−B catalyst dramatically revealed a markedly higher hydrogenation act...

Selective Hydrogenation of Furfural on Ni−P, Ni−B, and Ni−P−B Ultrafine Materials

Ni–P–B ultrafine amorphous alloy particles have been prepared by chemical reaction of nickel chloride, sodium hypophosphite, and potassium borohydride in aqueous solution. Two samples prepared at different initial pH values (pH=5 and 9) have been characterized by different experimental methods. X‐ray and electron diffraction indicated that both samples were amorphous in nature, and transmission electron microscopy gave average diameters of 50 and 30 nm for particles prepared at pH=5 and 9, respectively. X‐ray photoelectron spectroscopy revealed that nickel and phosphorus existed exclusively in their elemental states, while boron existed mainly in its elemental state but with some trace of its oxide on the surface. The crystallization process of the amorphous samples was investigated by differential scanning calorimetry and by x‐ray diffraction after annealing the samples at various temperatures. The results are correlated with the microstructure of the as‐prepared samples. It is found that when the initial pH of the reaction mixture is adjusted to 9, the pH value can be maintained automatically throughout the reaction and the sample thus formed has a fairly homogeneous microstructure.

Investigation of Ni–P–B ultrafine amorphous alloy particles produced by chemical reduction

Ni‐P ultrafine amorphous alloy particles have been prepared by reacting nickel chloride and sodium hypophosphite in an aqueous solution. X‐ray diffraction revealed the amorphous structure of the particles and transmission electron microscopy showed that the particles are spherical, with an average diameter of about 150 nm. X‐ray photoelectron spectroscopy confirmed that all nickel and phosphorus atoms are in the elementary state on the surface of the particles, which implied the alloying state of the particles. The dynamic process of the reaction has been studied. It is found that the reaction ended within 65 min at a pH value of 10 and 351 K when the sodium hypophosphite was exhausted, and the unreacted solid residue Ni(OH)2 should be washed out with ammonia solution to obtain ‘‘pure’’ Ni‐P ultrafine amorphous alloy particles.

The preparation of Ni-P ultrafine amorphous alloy particles by chemical reduction

The crystallization process of a−Fe35Ni15B26 ultrafine alloy particles prepared by chemical reduction with borohydride was investigated mainly by Mossbauer spectroscopy. The experimental results exhibit some new characteristics which were attributed to the microstructure of the sample.

Lifeng Zhang

Papers

Investigation of Ni–P–B ultrafine amorphous alloy particles produced by chemical reduction

The preparation of Ni-P ultrafine amorphous alloy particles by chemical reduction

The crystallization process of a−Fe35Ni15B26 ultrafine particles produced by reduction with borohydride