Unsupported CoNi x Mo sulfide hydrodesulfurization catalysts prepared by the thermal decomposition of trimetallic tetrab
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Unsupported CoNixMo sulfide hydrodesulfurization catalysts prepared by the thermal decomposition of trimetallic tetrabutylammonium thiomolybdate: effect of nickel on sulfur removal J. A. Medina Cervantes1 · R. Huirache‑Acuña1 · J. N. Díaz de León2 · S. Fuentes Moyado2 · J. Cruz‑Reyes3 · G. Alonso‑Núñez2 Received: 11 May 2020 / Accepted: 18 August 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract Herein we report the synthesis of unsupported bimetallic CoMo and trimetallic CoNiMo sulfide catalysts prepared by thermal decomposition (ex situ activation) of carbon-containing precursors and varying the nickel concentration for the hydrodesulfurization (HDS) of dibenzothiophene. The catalysts prepared were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma mass spectrometry and BET surface area measurements. The results from the characterization showed that the addition of an alkyl chained precursor results in non-porous catalysts with low surface area and high carbon content, which negatively affects the formation of crystalline phases such as molybdenum sulfide and their performance in the HDS reaction. Furthermore, the addition of nickel has a negative effect on the catalysts since it was observed that when it was added, the reaction rate values decreased and the catalyst with the highest catalytic activity turned out to be the CoMo catalyst. Although nickel catalysts generally have more affinity for hydrogenation reactions, unsupported trimetallic catalysts showed a preference for the direct desulfurization pathway. Keywords Ex situ activation · Unsupported · Alkyl chain · Hydrodesulfurization · Trimetallic catalysts
* R. Huirache‑Acuña [email protected] 1
Facultad de Ingeniería Química, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, C.P. 58060 Morelia, Michoacán, Mexico
2
Centro de Nanociencias Y Nanotecnología, Universidad Nacional Autónoma de México, KM. 107, Carretera Tijuana‑Ensenada, C.P. 22860 Ensenada, B.C., Mexico
3
Facultad de Ciencias Químicas, Universidad Autónoma de Baja California, C.P. 22390 Tijuana, B.C., Mexico
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Reaction Kinetics, Mechanisms and Catalysis
Introduction Currently, the amount of crude oil in the extraction fields is decreasing because of the growing worldwide demand for their products and energy. The oil industry is now refining heavy crudes, which by their nature, contain a higher quantity of “impurities” such as heterocyclic compounds that contain nitrogen and sulfur atoms in their structures [1, 2] making more difficult to refine the cuts, as well as provoking poisoning and deactivation of the catalyst in the downstream (i.e., reforming catalysts), as well as corrosion of pipelines, pumps, and refinery equipment. Furthermore, when the combustion reaction is carried out in the engines, these atoms appear in the polluting gases causing damage to the environment [3]. Nowadays, urban air quality is directly related to the quality of th
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