Hydrothermal Synthesis Of Ni-P Compounds For New Petroleum Refining Catalyst

In recent years, with the deterioration of the environment, the trend of the heavy oil and the more and more serious low-quality, the requirement of the high-performance oil hydro-treating catalyst were more and more urgent. Ni-P compounds, a new type of petroleum refining catalysts, has broad application prospects. Therefore, the study of the Ni-P compounds with a high catalytic performance becomes a hot research.In this paper, a new type of petroleum refining catalytic material--Ni-P compounds has been prepared; the impact of processing conditions on product in the preparation process of Ni-P compounds has been researched. Phase constitution, morphology and composition were determined by XRD, SEM and EDS, respectively. The major findings are as follows:(1) The preparation of Ni2P and Ni12P5 micron powders in the hydrothermal route and its characterizationsNi2P and Ni12P5 micron powders were synthesized via a hydrothermal reaction between nickel chloride (NiCl2·6H2O) and red phosphor (P). The effect on the final products of experimental conditions such as the molar ratio of red phosphor to nickel chloride and reaction temperature and time were discussed. The results are as follows:1) Increasing the P/Ni ratio helps the generation of Ni2P, lower P/Ni ratio is contributed to the formation of Ni12P5. Changing the P/Ni ratio does not have much impact on the morphology of the products, and the products remain the original morphology of red phosphorus. The reaction mechanism was the solid-liquid reaction mechanism. The concentration of Ni2+ in the solution is higher than that at the surface of red phosphor, so Ni2+ diffuses from the solution to red phosphor, where it reacts to produce Ni2P and Ni12P5.2) Below 200℃, the main phase is Ni2P, changing this temperature range, the phase of the products has no change. Raising the temperature to 210℃helps Ni12P5 generating, which is not conducive to the formation of Ni2P. 3) When the reaction time was increased from 12h to 24h, the final product was only Ni2P. Increasing reaction time from 24h to 48h, Ni12P5 will be the main phase. Increasing reaction time is beneficial to Ni12P5 formation, and has no influence to the morphology of products.(2) The preparation of Ni2P and Ni12P5 nano powders in the hydrothermal route and its characterizationsNi2P and Ni12P5 nano powders were synthesized via a hydrothermal reaction between nickel chloride (NiCl2·6H2O) and red phosphor (P). The effect on the final products of experimental conditions such as the molar ratio of red phosphor to nickel chloride and reaction temperature and time were discussed. The results are as follows:1) When the P/Ni≤15/1, the final product was only Ni12P5, When the P/Ni= 18/1, the main phase of the products was Ni2P. The TEM images of the nickel phosphide powders are similar to the ground red phosphor.2) 200℃is the ideal conditions of the generation of Ni2P, and the temperature increasing or decreasing will result in the emergence of a secondary phase Ni12P5 in the final products. Changes in temperature have no influence to the morphology of products.3) Changes in reaction time have enormous influence to the phase of the products. In different time periods, different products were created.(3) The preparation of the spherical Ni-P compounds and its characterizationThe spherical Ni-P compounds have been prepared via a hydrothermal reaction between nickel chloride (NiCl2·6H2O) and Sodium hypophosphite(NaH2PO3·H2O). XRD results show good crystallinity. EDS tests prove that the products were formed by two elements of nickel and phosphorus and were a nickel-rich Ni-P compounds. Increasing P/Ni value and extending the hydrothermal time will increase the P/Ni value. The P/Ni values and hydrothermal time have no significant impact on the morphology and the chemical composition of the products.