Selective hydrogenation of furfural on Ni-P, Ni-B, and Ni-P-B ultrafine materials

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: Ni_85.0P_15.0 ≫Ni_71.4B_28.9). By regulating a suitable P/B ratio, the ultrafine Ni-P-B catalyst dramatically revealed a markedly higher hydrogenation activity of furfural than Ni-P and Ni-B. The specific activities per surface area of the catalyst are in the order Ni_74.6P_12.1B_13.4 > Ni_72.5P_2.0B_25.5 > Ni_85.0P_15.0 ≫Ni_71.4B_28.9 > Raney nickel. The phosphorus is an active component to improve the selectivity of furfuryl alcohol. The hydrogenation of furfural is catalyzed actively by the Ni-P_x-E_y catalysts, following the first order with respect to the concentration of furfural. The nature of the ultrafine amorphous structure and the P/B ratio are the keys to manipulate the catalytic properties of Ni-P_x-B_y amorphous alloy catalysts.