制备方法对NiP非晶态合金性质及催化活性的影响

NiP amorphous alloy catalysts were prepared via three different ways, reduction of Ni2+ by NaH2PO2 (method 1), self-oxidation and reduction of Ni(H2PO2)2 (method 2), and the reduction of Ni2+ by H3PO2 with amine adjusting the pH value of solution (method 3). All the NiP samples have amorphous structure inferred from the X-ray Diffraction (XRD) patterns. But the catalysts prepared by the two new methods show smaller particle size and higher surface area than the samples by method 1, and they show higher catalytic activity in the hydrogenation of sulfolene evaluated in a 250 mL autoclave. In order to exhibit the influence of preparation methods on properties of NiP samples, three samples were prepared at the same conditions via different ways, respectively, which were signed as NiP-4 (from method 1), NiP-5 (from method 2) and NiP-9 (from method 3). Transmission Electron Microscope (TEM) images show these samples have different shapes and sizes. NiP-4 sample has not very regular shape. NiP-5 particles are isolated balls while the shape of NiP-9 is near spherical. Their average particle sizes are about 160?nm, 30?nm and 10?nm, respectively. Extend of surface oxidation increases with the particle size decreasing. Crystallization performance of these amorphous alloys is determined by Differential Scanning Calorimetry (DSC) analysis. Their crystallization temperature is in the order of NiP-9 (682 K) > NiP-5 (679 K) > NiP-4 (625 K), which means their structure stability in the same order.