Tuning hydrodearomatization performance of interstitial NixW alloy catalyst by controlling the doping of a small amount of tungsten

Abstract

Hydrogenation is an effective way to remove polycyclic aromatic hydrocarbons (PAHs). Unfortunately, traditional hydrogenation catalysts have insufficient activities for hydrodearomatization (HDA) reaction at low reaction temperatures. In this paper, we proposed a strategy to tune the HDA performance of interstitial NixW alloy catalysts by controlling the doping of tungsten. The characterization results show that the interstitial NixW alloy catalyst could be synthesized by reducing the bimetal oxide in hydrogen at 600 °C. As a comparison, tungsten oxide can only be reduced to WO2 without the addition of nickel. It was found that the interstitial NixW-600 alloy catalysts obtained at 600 °C showed better HDA activities than those catalysts obtained at 350 °C. Interestingly, the NixW-600 catalysts had excellent HDA activities at low reaction temperature. Especially, Ni7W/MCM-600 catalyst displayed the excellent selectivity of decalin (100%) at 140 °C and WHSV = 4 h−1, but Ni/MCM and Pt/MCM catalysts had no naphthalene conversion under this condition. Finally, we found that HDA activities of the NixW/MCM catalysts are extremely related to the composition of catalysts, the molar ratio of Ni/W, and reduction temperature. This strategy opens a convenient route and provides a prospective design guideline for constructing high-performance hydrogenation catalysts.