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2 pages, 171 KiB

Open AccessEditorial

Ni-Based Catalysts: Synthesis and Applications Today

by Roman G. Kukushkin and Petr M. Yeletsky

Catalysts 2023, 13(6), 968; https://doi.org/10.3390/catal13060968 - 2 Jun 2023

Viewed by 1224

Abstract

Transition-metal-based catalysts are widely used in various processes, in particular—nickel-based catalysts [...] Full article

(This article belongs to the Special Issue Ni-Based Catalysts: Synthesis and Applications)

Research

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16 pages, 3838 KiB

Open AccessEditor’s ChoiceArticle

Feasibility Assessment on Remanufacturing of Ni–Mo/γ–Al₂O₃ Catalyst for Residue Hydrodesulfurization

by Seon-Yong Ahn, Woo-Jin Na, Kyoung-Jin Kim, Beom-Jun Kim, Hea-Kyung Park and Hyun-Seog Roh

Catalysts 2023, 13(4), 738; https://doi.org/10.3390/catal13040738 - 13 Apr 2023

Cited by 4 | Viewed by 1305

Abstract

Residue hydrodesulfurization (RHDS) is a critical process in the petroleum refining industry for removing sulfur compounds from heavy residual oils. However, catalysts used in RHDS can easily be deactivated by numerous factors, leading to reduced process efficiency and economic benefits. The remanufacturing of [...] Read more.

Residue hydrodesulfurization (RHDS) is a critical process in the petroleum refining industry for removing sulfur compounds from heavy residual oils. However, catalysts used in RHDS can easily be deactivated by numerous factors, leading to reduced process efficiency and economic benefits. The remanufacturing of spent catalysts can be a useful strategy for extending the lifespan of catalysts, reducing waste, and improving process sustainability. This paper proposes an effective catalyst remanufacturing process for commercial RHDS catalysts. In detail, sequential unit processes including oil washing (OW), complete incineration (CI), and acid leaching (AL) were conducted to remanufacture the spent RHDS catalysts. We also highlight some of the key challenges in remanufacturing catalysts, such as the key factors involved in catalyst deactivation. Finally, we provide future perspectives on the development of an effective catalyst remanufacturing process for RHDS, with the goal of improving the efficiency, sustainability, and competitiveness of the petroleum refining industry. Full article

(This article belongs to the Special Issue Ni-Based Catalysts: Synthesis and Applications)

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14 pages, 3003 KiB

Open AccessArticle

Layered Double Hydroxide-Derived Ni-Mg-Al Catalysts for Ammonia Decomposition Process: Synthesis and Characterization

by Zaliya A. Fedorova, Vadim A. Borisov, Vera P. Pakharukova, Evgeniy Y. Gerasimov, Vladimir D. Belyaev, Tatyana I. Gulyaeva, Dmitriy A. Shlyapin and Pavel V. Snytnikov

Catalysts 2023, 13(4), 678; https://doi.org/10.3390/catal13040678 - 30 Mar 2023

Cited by 2 | Viewed by 1795

Abstract

Layered Ni-Mg-Al hydroxides with (Ni + Mg)/Al = 2.5 differing in Mg/Ni ratios and related oxide systems have been synthesized and characterized. Ni-Mg-Al hydroxides were prepared by the coprecipitation method. It was found that the samples dried at 110 °C were layered Ni-Mg-Al [...] Read more.

Layered Ni-Mg-Al hydroxides with (Ni + Mg)/Al = 2.5 differing in Mg/Ni ratios and related oxide systems have been synthesized and characterized. Ni-Mg-Al hydroxides were prepared by the coprecipitation method. It was found that the samples dried at 110 °C were layered Ni-Mg-Al hydroxides with a hydrotalcite-type structure. After the heat treatment at 600 °C, the formation of Ni-Mg-Al-mixed oxides with a specific nanostructure, an intermediate between a NaCl and spinel structure, took place. According to XRD data, it had the unit cell parameter a = 4.174–4.181 Å, and a crystallite size of 4.0 nm. The specific surface area of the Ni-Mg-Al samples dried at 110 °C was 45–54 m²/g, and that of those calcined at 600 °C was 156.1–209.1 m²/g. In agreement with HRTEM data, in all the synthesized nickel catalysts reduced at 700 °C (H₂), particle size was mainly distributed between 15–20 nm. The catalyst activity of LDH-derived Ni-Mg-Al catalysts in ammonia decomposition was studied in a fixed-bed flow-type reactor at an atmospheric pressure within the temperature range 500–700 °C. The synthesized catalysts overcame existing analogues in catalytic performance. At a process temperature of 500 °C, the Ni₂Mg₃Al₂-HT catalyst showed that the H₂ productivity was 23.8 mmol/(g_cat·min), exceeding the respective value of nickel catalysts reported in the literature. Full article

(This article belongs to the Special Issue Ni-Based Catalysts: Synthesis and Applications)

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18 pages, 8367 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Pt_1−xNi_x Alloy Nanoparticles Embedded in Self-Grown Carbon Nanofibers: Synthesis, Properties and Catalytic Activity in HER

by Anton A. Popov, Sofya D. Afonnikova, Andrey D. Varygin, Yury I. Bauman, Mikhail V. Trenikhin, Pavel E. Plyusnin, Yury V. Shubin, Aleksey A. Vedyagin and Ilya V. Mishakov

Catalysts 2023, 13(3), 599; https://doi.org/10.3390/catal13030599 - 16 Mar 2023

Cited by 9 | Viewed by 1543

Abstract

The development of new heterogeneous Pt-containing catalysts has retained its relevance over the past decades. The present paper describes the method to produce metal–carbon composites, Pt_1−xNi_x/CNF, with an adjustable Pt/Ni ratio. The composites represent Pt_1−xNi_x (x [...] Read more.

The development of new heterogeneous Pt-containing catalysts has retained its relevance over the past decades. The present paper describes the method to produce metal–carbon composites, Pt_1−xNi_x/CNF, with an adjustable Pt/Ni ratio. The composites represent Pt_1−xNi_x (x = 0.0–1.0) nanoparticles embedded within a structure of carbon nanofibers (CNF). The synthesis of the composites is based on a spontaneous disintegration of Pt_1−xNi_x alloys in an ethylene-containing atmosphere with the formation of CNF. The initial Pt_1−xNi_x alloys were prepared by thermolysis of multicomponent precursors. They possess a porous structure formed by fragments of 100–200 nm. As was shown by X-ray diffraction analysis, the crystal structure of the alloys containing 0–30 and 60–100 at.% Ni corresponds to a fcc lattice based on platinum (Fm-3m), while the Pt_0.50Ni_0.50 sample is an intermetallic compound with the tetragonal structure (P4/mmm). The impact of the Ni content in the Pt_1−xNi_x samples on their activity in ethylene decomposition was studied as well. As was revealed, the efficiency of Pt_1−xNi_x alloys in this process increases with the rise of Ni concentration. The composite samples were examined in an electrochemical hydrogen evolution reaction. The synthesized Pt_1-xNi_x/CNF composites demonstrated superior activity if compared with the Pt/Vulcan commercial catalyst. Full article

(This article belongs to the Special Issue Ni-Based Catalysts: Synthesis and Applications)

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14 pages, 2287 KiB

Open AccessArticle

Catalysts Based on Ni(Mg)Al-Layered Hydroxides Prepared by Mechanical Activation for Furfural Hydrogenation

by Liudmila N. Stepanova, Elena O. Kobzar, Mikhail V. Trenikhin, Natalia N. Leont’eva, Aleksandra N. Serkova, Aleksei N. Salanov and Aleksandr V. Lavrenov

Catalysts 2023, 13(3), 497; https://doi.org/10.3390/catal13030497 - 28 Feb 2023

Cited by 2 | Viewed by 1133

Abstract

Ni(Mg)Al-layered hydroxides with molar ratios of (Ni + Mg)/Al = 2, 3, 4 and Ni/(Ni + Mg) = 0.1, 0.3, 0.5, 0.7 were synthesized by mechanochemical activation. It has been proven that the phase composition of the samples was presented by a single [...] Read more.

Ni(Mg)Al-layered hydroxides with molar ratios of (Ni + Mg)/Al = 2, 3, 4 and Ni/(Ni + Mg) = 0.1, 0.3, 0.5, 0.7 were synthesized by mechanochemical activation. It has been proven that the phase composition of the samples was presented by a single hydrotalcite phase up to Ni/(Ni + Mg) = 0.5. For the first time, catalysts based on Ni(Mg)Al-layered hydroxides prepared by a mechanochemical route have been studied in the reaction of furfural hydrogenation. The correlation between furfural conversion, the selectivity of the products, and the composition of the catalysts was established. The effect of phase composition, surface morphology, and microstructure on the activity of the catalysts was shown by XRD, SEM, and TEM. It was found that catalysts with Ni/(Ni + Mg) = 0.5 have the highest furfural conversion. Herewith, the product selectivity can be regulated by the (Ni + Mg)/Al ratio. Full article

(This article belongs to the Special Issue Ni-Based Catalysts: Synthesis and Applications)

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16 pages, 12609 KiB

Open AccessArticle

Unsupported Ni—Mo—W Hydrotreating Catalyst: Influence of the Atomic Ratio of Active Metals on the HDS and HDN Activity

by Ksenia A. Nadeina, Sergey V. Budukva, Yuliya V. Vatutina, Polina P. Mukhacheva, Evgeniy Yu. Gerasimov, Vera P. Pakharukova, Oleg V. Klimov and Aleksandr S. Noskov

Catalysts 2022, 12(12), 1671; https://doi.org/10.3390/catal12121671 - 19 Dec 2022

Cited by 5 | Viewed by 1654

Abstract

Hydrotreating is one of the largest processes used in a refinery to improve the quality of oil products. The great demand of the present is to develop more active catalysts which could improve the energy efficiency of the process when it is necessary [...] Read more.

Hydrotreating is one of the largest processes used in a refinery to improve the quality of oil products. The great demand of the present is to develop more active catalysts which could improve the energy efficiency of the process when it is necessary for heavier feedstock to be processed. Unsupported catalysts could solve this problem, because they contain the greatest amount of sulfide active sites, which significantly increase catalysts’ activity. Unfortunately, most of the information on the preparation and properties of unsupported catalysts is devoted to powder systems, while industrial plants require granular catalysts. Therefore, the present work describes a method for the preparation of granular Ni—Mo—W unsupported hydrotreating catalysts and studies the influence of the Ni/Mo/W atomic ratio on their properties. Catalysts have been prepared by plasticizing Ni—Mo—W precursor with aluminum hydroxide followed by granulation and drying stages. Ni—Mo—W precursor and granular catalysts were studied by X-ray diffraction (XRD), nitrogen adsorption–desorption method, high-resolution transmission electron microscopy (HRTEM), and thermal analysis. Granular catalysts were sulfided through a liquid-phase sulfidation procedure and tested in hydrotreating of straight-run vacuum gasoil. It was shown that the Ni/Mo/W atomic ratio influenced the formation and composition of active compounds and had almost no influence on the textural properties of catalysts. The best hydrodesulfurization (HDS) activity was obtained for the catalyst with Ni/Mo/W ratio—1/0.15/0.85, while hydrodenitrogenation (HDN) activity of the catalysts is very similar. Full article

(This article belongs to the Special Issue Ni-Based Catalysts: Synthesis and Applications)

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16 pages, 3108 KiB

Open AccessArticle

Advanced High-Loaded Ni–Cu Catalysts in Transfer Hydrogenation of Anisole: Unexpected Effect of Cu Addition

by Alexey Philippov, Nikolay Nesterov, Vera Pakharukova, Ivan Kozhevnikov and Oleg Martyanov

Catalysts 2022, 12(11), 1307; https://doi.org/10.3390/catal12111307 - 25 Oct 2022

Cited by 9 | Viewed by 1716

Abstract

Binary Ni–Cu heterogeneous catalysts are known to demonstrate excellent activity in conventional hydrogenation of phenolic compounds, and Cu addition facilitates hydrodeoxygenation (HDO). In this study, we aimed to show the effect of Cu on the specific catalytic activity and selectivity of Ni–Cu catalysts [...] Read more.

Binary Ni–Cu heterogeneous catalysts are known to demonstrate excellent activity in conventional hydrogenation of phenolic compounds, and Cu addition facilitates hydrodeoxygenation (HDO). In this study, we aimed to show the effect of Cu on the specific catalytic activity and selectivity of Ni–Cu catalysts in transfer hydrogenation, in which 2-PrOH was used as a solvent and an H donor. Catalytic transformations of anisole were studied in sub- and supercritical alcohol at 150 and 250 °C. The catalysts were prepared using an environmentally friendly supercritical antisolvent coprecipitation method, which makes it possible to obtain well-dispersed particles (less than 7 nm) at high metal loading (up to 50 wt.%). When copper is added, deactivation of the catalyst in transformations of anisole, including HDO, is observed. The experimental data and the appropriate kinetic analysis demonstrate that there is a decrease in the rate of anisole conversion accompanied by an increase in the concentration of acetone formed during the dehydrogenation of 2-PrOH. Full article

(This article belongs to the Special Issue Ni-Based Catalysts: Synthesis and Applications)

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10 pages, 729 KiB

Open AccessArticle

Two-Step Esterification–Hydrogenation of Bio-Oil to Alcohols and Esters over Raney Ni Catalysts

by Ying Xu, Limin Zhang, Wei Lv, Chenguang Wang, Congwei Wang, Xinghua Zhang, Qi Zhang and Longlong Ma

Catalysts 2021, 11(7), 818; https://doi.org/10.3390/catal11070818 - 5 Jul 2021

Cited by 6 | Viewed by 2172

Abstract

Fast pyrolysis bio-oil is very difficult to be used because of its acidity, instability, high degree of unsaturation, etc. Processes for property upgrading are necessary and required. In this study, three kinds of Raney Ni catalysts were prepared and used to investigate two-step [...] Read more.

Fast pyrolysis bio-oil is very difficult to be used because of its acidity, instability, high degree of unsaturation, etc. Processes for property upgrading are necessary and required. In this study, three kinds of Raney Ni catalysts were prepared and used to investigate two-step esterification–hydrogenation (TEH) to upgrade the light fraction of bio-oil. The results show that the first step in esterification markedly decreased the content of active compounds such as acids and ketones and aldehydes and increased the content of alcohols and esters (from 10.53% to 47.55%), which improved the bio-oil stability and was favorable for the following hydrogenation reaction. The second step of TEH (hydrogenation) further improved the quality of the bio-oil over Raney Ni and metal-modified Raney Ni catalysts at 140 °C. In particular, the Mo-RN catalyst displayed the best hydrogenation effect, with only 5.44% of acid content, and the stable component content reached 90.16%. This may be attributed to the higher hydrogenation activity from Raney Ni combined with acid MoO_x species and the thermal stability of the catalyst. Moreover, the obtained upgraded bio-oil mixture could be used as a solvent for raw bio-oil’s esterification. Therefore, it has the potential to reduce methanol solvent usage and energy consumption for solvent separation during the two-step treatment of raw bio-oil in this context. Compared with the OHE (one-step esterification-hydrogenation) process, THE showed a better performance for raw bio-oil upgrading with higher alcohols and stable compounds, which is more favorable for the saturation and stability of bio-oil’s complex components step by step. Full article

(This article belongs to the Special Issue Ni-Based Catalysts: Synthesis and Applications)

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