Surface Carbon Activated NiMo/TiO2 Catalyst Towards Highly Efficient Hydrodesulfurization Reaction

Abstract

By adopting molecular self-assembly, the surface of mesoporous TiO2 whiskers (TiO2(w)) was modified with 18 alkyl phosphate as carbon source. This method was successfully used to form a carbon heterogeneous monolayer on titania surface (TiO2(w)–C) under N2 atmosphere. Novel NiMo/TiO2(w)–C catalysts were prepared by incipient-wetness impregnation. The carriers and catalysts were characterized by N2 adsorption–desorption measurements, NH3-temperature-programmed desorption, Raman Spectra, Fourier transform infrared, scanning electron microscopy, temperature-programmed reduction, and H2S-temperature-programmed desorption. The catalytic activity of TiO2(w)–C as a support, together with the effect of carbon content on hydrodesulfurization (HDS) activity of NiMo/TiO2(w)–C was investigated. The results showed that NiMo/TiO2(w)–C exhibited higher HDS catalytic activity under conditions of low temperature and pressure (280 °C and 2 MPa). Under such mild reaction conditions, NiMo/TiO2(w)–C-0.5 with carbon loading of 0.5 % showed the highest HDS result (100 %). The improved activity of NiMo/TiO2(w)–C-0.5 can be attributed to the TiO2(w) modifying with trace amounts of carbon, which would increase the total acid sites and suppress the carbon deposition on the surface of catalyst. Additionally, the generated carbon nanoparticles can weaken the interaction between TiO2(w) and the HDS product (H2S) and then improve H2S desorption from the catalyst surface, which lead to the outstanding HDS activity.