Advances in chemical synthesis and application of metal-metalloid amorphous alloy nanoparticulate catalysts

Abstract

This paper reviews the advances in the chemical synthesis and application of metal-metalloid amorphous alloy nanoparticles consisting of transition metal (M) and metalloid elements (B, P). After a brief introduction on the history of amorphous alloy catalysts, the paper focuses on the properties and characterization of amorphous alloy catalysts, and recent developments in the solution-phase synthesis of amorphous alloy nanoparticles. This paper further outlines the applications of amorphous alloys, with special emphasis on the problems and strategies for the application of amorphous alloy nanoparticles in catalytic reactions. History of amorphous alloy catalystAmorphous alloys have been extensively investigated internationally over the last 50 years largely spurred by their unique electronic, magnetic and surface properties and their increasing utility in a broad range of applications [1,2]. The amorphous alloy nanoparticles have gained increasing attention as novel catalytic materials since 1980, with the unique isotropic structure and high concentration of coordinatively unsaturated sites leading to catalytic activity and selectivity superior to their crystalline counterparts [3]. Especially, amorphous alloys chemically reduced by borohydride (BH 4 − ) and hypophosphite (H 2 PO 2 − ) have nanosized morphology and consequently higher surface area and activity than those prepared by the quenching method [4][5][6][7][8]. It has been regarded that the amorphous alloy catalyst can be a potential alternative to Raney nickel or noble metal catalyst in catalytic hydrogenation. Raney nickel has shown many serious disadvantages, such as short lifetimes due to poor sulfur resistance and environmental pollution caused by alkaline leaching during preparation. In contrast, the amorphous alloy nanoparticulate catalysts are inexpensive, environmentally benign, and effective catalytic materials.For the chemical synthesis of metal-metalloid amorphous alloy catalysts, Brown et al. and Paul et al. found that the NiB particles reduced by sodium borohydride in water or ethanol solution showed excellent catalytic activity and selectivity in many hydrogenation reactions [9][10][11][12][13][14][15]. After that, and Chen et al. [21][22][23][24] studied the mechanism of borohydride reduction and the relation between properties and preparation conditions. On the other hand, Deng and coworkers have been interested in studying the properties of amorphous alloy particles and the application of metal boron (MB) and metal phosphorus (MP) amorphous alloys for catalytic hydrogenation [25-37]. Dragieva et al. focused on developing amorphous alloys as electrode or catalytic oxidation materials [38-43], while Chen and coworkers prepared MPB alloy nanoparticle catalysts for various selective hydrogenation reactions [44-50]. Amorphous alloy nanoparticulate catalysts have been widely studied by different research groups in China [51-60]. Among them, our group has attempted to develop NiB and NiP industrial amorphous alloy catalysts in various catalyt...

Synthesis of nickel nanoparticles supported on metal oxides using electroless plating: Controlling the dispersion and size of nickel nanoparticles

“…Supported nickel nanoparticles have been reported frequently in magnetic science and catalysis science. In particular, nickel nanoparticles supported on metal oxides with unique chemical and physical properties have been widely used as catalysts for many hydrorelated reactions, such as the hydrogenation, hydrogenolysis, and hydrotreating reactions [1][2][3][4][5][6]. Such supported nickel nanoparticles are mostly synthesized by the impregnation/deposition of nickel complexes from an aqueous solution onto the supports [4].…”

“…Indeed, a new method for the synthesis of supported nickel nanoparticles with high dispersion as well as high nickel loading is significant for their further catalytic application. The electroless nickel-plating method should be a suitable choice because it has been proved to control the nickel loading, particle size, and dispersion of nickel nanoparticles [4][5][6].…”

“…The plating occurs by the reduction of nickel ions at the surface of the active substrate immersed into the plating solution and continues to deposit on the substrate through a catalytic action of the deposit itself [7][8][9]. Two mechanisms of electroless plating with borohydride as reductant have been reported by Gorbunova (Scheme S1) and Mallory (Scheme S2) [5,6,[10][11][12][13]. Three routes for the activation of electroless nickel plating are proposed based on the two mechanisms and the work of Hwang and Lin as shown in Fig.…”

Amorphization and thermal stability of aluminum-based nanoparticles prepared from the rapid cooling of nanodroplets: effect of iron addition

“…In recent years, amorphous nanomaterials have attracted increasing interest because of their scientific importance and promising applications in optics, electronics, and catalysis. [8][9][10][11] For example, Lu et al found that pressure-induced amorphous Ta 2 O 5 nanowires show significant improvement in electrical conductivity. 12 In contrast to the corresponding crystalline nanoparticles of the same mean diameter, the amorphous Cu nanoparticles showed a low-energy shift of surface plasmon resonance.…”

An effective method for increasing the activity of nickel boride catalyst nano-particles in hydrogenation reactions: Low-temperature hydrogen treatment

“…Nickel boride nano-catalysts have gained increasing interest as novel catalytic materials in hydrogenation reactions [1]. The high concentration of coordinating unsaturated active sites in these amorphous alloy nano-particles donates them higher activity and selectivity with respect to their crystalline counterparts [2].…”