Synthesis and Characterization of NiWS2/MWCNT Nanohybrids

Abstract

The present research work mainly focuses on the synthesis and characterization of NiWS₂/MWCNT_-f nanohybrids. Multi-walled carbon nanotubes MWCNT_-r were previously purified with HCl to obtain MWCNT_-p, then were treated with an acid mixture of HNO₃ : H₂SO₄ (6 M) at 1 : 3 v/v to generate functionalization on the surface with oxygen as hydroxylic and carbonyl groups to obtain MWCNT_-f. The synthesis of the nanohybrids was carried out by the sequential incipient impregnation method using ammonium thiotungstate (ATT) and nickel chloride as metal precursors. The effect of nickel was evaluated by modifying its atomic ratio with respect to tungsten with values of R= (Ni/Ni+W) equal to 0.3 and 0.5. Subsequently, the nanohybrids were obtained by thermal decomposition in argon atmosphere and an activation method using H₂/H₂S. Once the nanohybrids were obtained, their structural properties were characterized by Raman spectroscopy, BET, HRTEM, XRD, and TGA analyses. The formation of the nanohybrids was achieved obtaining the active phase WS₂ and NiWS supported on MWCNT_-f, which was corroborated by HRTEM and XPS spectroscopy techniques. These materials are important candidates as catalysts in the hydrodesulfurization reactions.