Ni2P Catalyst for Hydrodesulfurization

More and more rigorous environmental regulations limiting the emissions of sulfur dioxide and the continuing decline in the quality of petroleum feedstocks have given rise to the need for investigation and development of high-performance hydrodesulfurization (HDS) catalysts. This paper provides a review of recent progress in the characteristics, active phase, synthesis, modification and HDS catalytic performance of Ni2P catalyst. There are two types of initial active sites in Ni2P. The Ni (1) initial active sites have a tetrahedral geometry, and which are involved in the direct desulfurization pathway in HDS. The Ni (2) initial active sites have a square pyramidal geometry, and which are responsible for the high catalytic activity in the hydrogenation pathway in HDS. A surface nickel phosphosulfide phase may be formed under HDS reaction, and which is considered as the real active phase. Ni2P is mainly prepared by temperature-programmed reduction and liquid phase synthesis. The support, promoter and complex agent have important effect on the formation of Ni2P active phase, as well as the catalytic activity. Compared with commercial sulfide catalyst, the Ni2P catalyst shows higher HDS activity for thiophene, dibenzothiophene and 4, 6-dimethyldibenzothiophene.