Supported Ni2P catalysts derived from nickel phyllosilicate with enhanced hydrodesulfurization performance

Abstract

Highly dispersed Ni2P catalysts were prepared from nickel phyllosilicate precursor, which was generated on the support by the deposition–precipitation (DP) method. Si-containing materials, including SiO2, MCM-41, S-1, and TS-1, were used as the supports. The strong interaction between Ni and Si species in nickel phyllosilicate effectively suppressed the agglomeration of nickel species. Highly dispersed Ni2P catalyst (Ni2P/SiO2-DP) was obtained by subsequent temperature-programmed hydrogen reduction, and the size of Ni2P crystallites was smaller than that of Ni2P/SiO2-IM prepared from conventional impregnation precursor (7.7 nm vs 14.2 nm). HRTEM observation demonstrated that a large fraction of (201) planes were present in Ni2P/SiO2-DP whereas (111) planes were predominant in Ni2P/SiO2-IM. The strong metal-support interaction and the smaller particle size, along with the higher degree of coordinately unsaturated sites facilitated the hydrogen spillover and the hydrogenation activity. As a result, Ni2P/SiO2-DP exhibited significantly higher performance than Ni2P/SiO2-IM in hydrodesulfurization of 4,6-dimethyldibenzothiophene. Similarly, highly dispersed Ni2P catalysts supported on Si-containing molecular sieves (MCM-41, S-1, and TS-1) were obtained from the in situ generated nickel phyllosilicate as well. It seems that the strong interaction between Ni and Si species in nickel phyllosilicate precursor played a decisive role in the formation of highly dispersed and (201) plane-exposed Ni2P catalysts.