Affiliation:
1. State Key Laboratory of Fine Chemicals School of Chemical Engineering Dalian University of Technology Dalian 116024 P. R. China
2. Tianjin Key Laboratory of Brine Chemical Engineering and Resource Eco-utilization College of Chemical Engineering and Materials Science Tianjin University of Science and Technology Tianjin 300457 P. R. China
3. Liaoning Key Laboratory of Petrochemical Technology and Equipment Dalian University of Technology Dalian 116024 P. R. China
Abstract
AbstractA series of physical mixtures of Na4P2S6 and NiCl2 (P‐NiPS(x), where x represents the P/Ni molar ratio) were employed for the preparation of Ni2P. For comparison, a sulfur‐containing Ni2P catalyst (Ni2P‐S) and a sulfur‐free Ni2P catalyst (Ni2P‐TPR) were prepared by reduction of Ni2P2S6 and a nickel phosphate precursor, respectively. The reduction of the P‐NiPS(x) precursors with P/Ni ratios above 2/3 yielded Ni2P catalysts with a distinct nickel phosphosulfide layer (NiPS(x)), and the Ni2P phase started to form at ca. 200 °C. The reduction of Ni2P2S6 to Ni2P most likely follows a disproportionation mechanism. The P3+ species in Ni2P2S6 disproportionate to PH3 and P5+ during the reduction, and PH3 further reacts with nickel and sulfur species to form Ni2P and the surface nickel phosphosulfide layer. The sulfur atoms in the nickel phosphosulfide phase were in the form of S2−. The introduction of sulfur to Ni2P favored the hydrogenation pathway of the hydrodesulfurization (HDS) of dibenzothiophene (DBT), but hardly affected the direct desulfurization (DDS) pathway and inhibited the hydrogenation of biphenyl. The DDS pathway rate constants of DBT HDS over the Ni2P‐TPR and NiPS(x) catalysts were observed to increase linearly with the increase in their surface Ni atomic concentrations.
Funder
National Natural Science Foundation of China
Natural Science Foundation of Tianjin Municipality