Highly Active Bulk Mo(W)S2 Hydrotreating Catalysts Synthesized by Etching out of the Carrier from Supported Mono- and Bimetallic Sulfides

Abstract

A bulk MoWS₂ catalyst has been synthesized by acid etching of the carrier from the supported MoWS₂/Al₂O₃ catalyst obtained on the basis of the mixed bimetallic heteropoly acid (HPA) H₄[SiMo₃W₉O₄₀]. As reference samples, monometallic MoS₂ and WS₂ catalysts have been prepared from the corresponding supported analogues, as well as a Mo + WS₂ sample based on a mechanical mixture of monometallic HPA in the atomic ratio of Mo/W = 1/3. The catalytic properties of the synthesized catalysts have been studied in model reactions of hydrodesulfurization (HDS) of dibenzthiophene (DBT) and hydrogenation (HYD) of naphthalene in a flow unit. It has been shown that the catalytic activity of the samples in both the DBT HDS and naphthalene HYD reactions increases in the following order: MoS₂ < WS₂ < Mo + WS₂\( \ll \) MoWS₂. It has been found that the bulk tungsten-containing catalysts exhibit higher specific catalytic activity than the supported counterparts. Increased values of hydrogen uptake according to the results of hydrogen temperature-programmed reduction for the bulk catalysts indicate an increase in the number of active sites and the formation of a more effective active phase compared to supported catalysts.