Preparation Of Nickel Phosphide Catalyst And Its Hydrogenation Performance

This paper presents a new method for the preparation of highly active nickel phosphide(Ni2P)catalyst by self-reduction.The self-reduction method synthesized Ni2 P using nickel acetate as the nickel source and ammonium hypophosphite as the phosphorus source,and synthesized the Ni2 P catalyst under the protection of N2 atmosphere at 400 o C.This synthesis method is simple,and the calcination step of precursor was not needed.The preparation process does not require hydrogen,which is energy-efficient,safe and economical.The effects of different initial P/Ni molar ratios on the formation of Ni2 P active phase were investigated.A series of supported Ni2 P catalysts were prepared with different self-reduction temperature and three different supports.The prepared catalyst was characterized by XRD,N2 isothermal adsorption,CO adsorption,XPS,SEM and TEM.The effects of supports and temperature on the hydrodesulfurization(HDS)and hydrodeoxidation(HDO)performances of supported Ni2 P catalysts were investigated using dibenzothiophene(DBT)and benzofuran(BF)as model compounds.The results showed as follows,(1)When the P/Ni is less than 4,the prepared catalyst is not pure Ni2 P phase,which contains Ni(PO3)2 and Ni5P4 phase.When P/Ni is equal and greater than 4,pure Ni2 P phase can be obtained.(2)When the reduction temperature is 350 °C at N2 atmosphere,the Ni2 P cannot be informed;When the reduction temperature increased to400 °C,a single Ni2 P active phase can obtained.As the reduction temperature increasing,the Ni2 P active phase particles size gets smaller and disperser.The catalyst synthesized at higher temperature possesses a larger surface area and lower surface accumulation of phosphate.(3)With the increase of reduction temperature,the HDO and HDS activity of Ni2P/C-x catalysts increased;When the reduction temperature increased to 500 ° C,the increase of temperature has not impact on HDO and HDS activity.(4)At the condition of WHSV=4.0 h-1?H2/Oil of500(V/V)and 3.0 MPa,over the Ni2P/C-500 °C catalyst,the BF conversion was 91%,the yields of O-free products was 77%,the DBT conversion was 88%.(5)The Ni2P/Ti O2 catalyst with Ti O2 support has the highest HDOand HDS activity.At the condition of WHSV=4.0 h-1?H2/Oil of 500(V/V)and reaction pressure of 3.0 MPa,the conversion rate of BF is 90%,and the conversion rate of DBT is 88%.The HDO and HDS activity order of preparated catalysts with different support were Ni2P/Ti O2 > Ni2P/C > Ni2P/MCM-41.