Nickel phosphides

The thermodynamic measurements for nickel phosphides were recently summarised by Schlesinger [2002SCH] (in that reference, red phosphorus (V) was used as the standard state for phosphorus). Schlesinger concluded that the details of the Ni-P phase diagram remain controversial, and that the available data are insufficient to allow calculation of assessed thermodynamic values for any nickel phosphides. No values are selected in the present review. 

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This paper describes the catalytic activity of nickel phosphide supported on silica, alumina, and carbon-coated alumina in the hydrodesulfurization of 4,6-dimethyldibenzothiophene. The catalysts are made by the reduction of phosphate precursors. On the silica support the phosphate is reduced easily to form nickel phosphide with hi catalytic activity, but on the alumina support interactions between the phosphate and the alumina hinder the reduction. The addition of a carbon overlayer on alumina decreases the interactions and leads to the formation of an active phosphide phase. 

H. A. Rowland,2 and M. N. Saha could find no evidence in the solar spectrum of the existence of phosphorus in the sun but phosphorus of extra-terrestrial origin has been found in meteorites. 0. C. Farrington reported the occurrence of free phosphorus in the meteorite which fell in Saline Township. Iron phosphide, and iron nickel phosphide have been found in numerous meteorites 3—vide infra, iron phosphide, and schreibersite, and rhabdite. 

Better yields were obtained by the electrolysis of 1 to 2 per cent, sulphuric acid using anodes of copper or nickel phosphide.6... 

Figure 24 Magnetic ordering temperatures of uranium nickel phosphides with crystal structures belonging to two different structural families (from Ebel et al )...

K. Sugiyama, Chemical Vapor Deposition of Nickel Phosphide Ni P, Journal of Less-Common Metals, Vol.64,1979, pp. 101-106. 

Muchnik, S. V., Formation of nickel phosphides under combustion conditions. Izv. Akad. Nauk SSSR, Nearg. Mater., 20,158 (1984). 

Na2H20O14Se sodium selenate decahydrate 10102-23-5 25.00 1.6100 1 3172 Ni2P nickel phosphide 12035-64-2 25.00 7.3300 1... 

Reaction of nickel chloride with aqueous NaH2P02 gave a precipitate of a nickel phosphide labeled NiP-1. When a 50% aqueous ethanol solution was used, the NiP-2 catalyst was produced. While these materials had some catalytic activity they were inferior to the nickel borides. 

X-ray photoelectron (XPS) studies of nickel boride, nickel phosphide, Raney nickel and Urushibara nickel showed that the electron density on the nickel was a function of the other metal present in these catalysts. 28J29 Boron, aluminum (Raney nickel) and zinc (Urushibara nickel) all increased the electron density on the nickel while phosphorous was an electron acceptor. Comparing the electron densities on the nickel in these catalysts with that on a nickel black prepared by the thermal decomposition of nickel formate (D-Ni) gave the series Ni-B > Ni-Al > Ni-Zn > D-Ni > Ni-P. 

A parameter, Aq, was defined as the relative change in electron density on nickel resulting from electron transfer between nickel and the second element as compared with that on nickel black. Table 12.2 shows the Aq values for these different nickel catalysts. 29 That for the P-1 nickel boride25 is the most negative and that for the NiP-1 nickel phosphide is the most positive. In Fig. 12.5 is shown the relationship between the areal turnover frequencies for the hydrogenation of styrene over these catalysts and their Aq values. 29 These data... 

Layman KA, Bussell ME (2004) Infrared spectroscopic investigation of thiophene adsorption on silica-supported nickel phosphide catalysts. J Phys Chem B 108 15791... 

Phosphorus occurrence in the lithosphere is predominantly as phosphates, P04 , although a rare iron-nickel phosphide, schreibersite ((Fe, Ni)3P)g is also known in nature [1]. For this reason, phosphates are the primary source of elemental phosphorus for chemical process requirements. Only 0.20-0.27% phosphate (0.15-0.20% as P2O5 0.07-0.09% as P) is present in ordinary crustal rocks. 

Our research on supported transition-metal phosphides started with the preparation of nickel phosphides supported on an amorphous Si02 carrier. Si02 was preferred to AI2O3 as it interacts to a lesser extent with phosphates, which are known to form aluminum phosphates in the presence of AI2O3 [21]. The latter was already used as a support for MoP [22], but the authors had to introduce high loadings of molydenum and phosphorus... 

Microcalorimetric measurements of CO and H2 adsorption at 308 K have been performed on nickel powder, nickel boride (Ni-B) and nickel phosphide (Ni-P) in order to establish the effects of B and P on nickel [141]. The initial values of Qdiff ox CO and H2 adsorption on reduced Ni powder were 120 and 85 kJ mol, respectively. The presence of B or P decreased the initial heats of CO and H2 adsorption (by 20 and 10 kJ mof respectively for B, and by 30 and 20 kJ mof for P), and also decreased the saturation uptakes of probe molecules per unit surface area. 

Heat treatment of the amorphous deposit above about 240°C results in the formation of some crystalline nickel phosphide, NijP, and a consequent increase in hardness. Some metal phosphides may be present before heat treatment. 

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