Catalysts

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3 pages, 157 KiB

Open AccessEditorial

Ni-Containing Catalysts

by Patrick Da Costa

Catalysts 2021, 11(5), 645; https://doi.org/10.3390/catal11050645 - 19 May 2021

Cited by 1 | Viewed by 2404

Abstract

Murray Raney used Nickel for the first time as a hydrogenation catalyst over one century ago [...] Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

Research

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12 pages, 4242 KiB

Open AccessArticle

Carbon Deposition Behavior of Ni Catalyst Prepared by Combustion Method in Slurry Methanation Reaction

by Keming Ji, Fanhui Meng, Jiayao Xun, Ping Liu, Kan Zhang, Zhong Li and Junhua Gao

Catalysts 2019, 9(7), 570; https://doi.org/10.3390/catal9070570 - 28 Jun 2019

Cited by 14 | Viewed by 3824

Abstract

Ni/Al₂O₃ catalyst prepared by combustion method was applied in a slurry methanation reaction to study the catalytic performance, especially the regeneration performance. The catalyst properties were characterized by (X-Ray diffraction) XRD, Inductively coupled plasma atomic emission spectrometer (ICP-AES), Nitrogen adsorption-desorption, [...] Read more.

Ni/Al₂O₃ catalyst prepared by combustion method was applied in a slurry methanation reaction to study the catalytic performance, especially the regeneration performance. The catalyst properties were characterized by (X-Ray diffraction) XRD, Inductively coupled plasma atomic emission spectrometer (ICP-AES), Nitrogen adsorption-desorption, Transmission electron microscopy (TEM), Thermogravimetric analysis (TG/DTG), Temperature programmed oxidation (TPO), and H₂ chemisorption before and after reaction. The results show that the catalyst deactivation was mainly due to carbon deposition, which exhibited amorphous carbon films and formed by the disproportionation of CO. The carbon deposition was formed on the catalyst surface and existed as carbon films during the reaction, then it gradually separated from the catalyst surface, generated an overlapping multi-layer three-dimensional carbon structure, which covered the active site and blocked the pores. As a result, the metal surface area of catalyst decreases, as well as the activity. The carbon deposition could be removed by oxidative calcination without destroying the catalyst structure, the active sites could be re-exposed and the catalyst activity could be recovered. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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16 pages, 4859 KiB

Open AccessArticle

Computational Investigation of Nickel-Mediated B–H Activation and Regioselective Cage B–C(sp²) Coupling of o-Carborane

by Wei-Hua Mu, Wen-Zhu Liu, Rui-Jiao Cheng, Li-Juan Dou, Pin Liu and Qiang Hao

Catalysts 2019, 9(6), 548; https://doi.org/10.3390/catal9060548 - 18 Jun 2019

Cited by 3 | Viewed by 3902

Abstract

Density functional theory (DFT) methods including LC-ωPBE, CAM-B3LYP, B3LYP, and B3LYP-D3, combined with double Zeta all-electron DZVP basis set, have been employed to conduct computational investigations on nickel-mediated reaction of o-carboranylzirconacycle, n-hexene, and 2-bromophenyltrimethylsilylacetylene in toluene solution. A multistep mechanism leading [...] Read more.

Density functional theory (DFT) methods including LC-ωPBE, CAM-B3LYP, B3LYP, and B3LYP-D3, combined with double Zeta all-electron DZVP basis set, have been employed to conduct computational investigations on nickel-mediated reaction of o-carboranylzirconacycle, n-hexene, and 2-bromophenyltrimethylsilylacetylene in toluene solution. A multistep mechanism leading to the C,C,B-substituted carborane-fused tricyclics, including (1) sequential insertion of alkene and alkyne into Ni–C bonds; (2) double 1,2-migration of the TMS group; (3) B–H activation assisted by Cs₂CO₃ additive; and (4) reduction cage B–C (sp²) coupling, was proposed. Among these steps, the B–H activation of o-carborane was located as rate-determining step (RDS). With assistance of Cs₂CO₃ additive (replaced by K₂CO₃ in simulation), the RDS free-energy barrier at PCM-LC-ωPBE/DZVP level was calculated to be 23.1–23.9 kcal·mol⁻¹, transferring to a half-life of 3.9–15.1 h at 298 K. The predicted half-life coincides well with 80% experimental yields of C,C,B-substituted carborane-fused tricyclics after 12 h. Kinetic data obtained by employing LC-ωPBE method also reproduced the experimental diastereoselective ratio well. Various B–H activation pathways with and without Cs₂CO₃ additive were taken into consideration, which illustrates Cs₂CO₃ as an essential guarantee for smooth occurrence of this reaction at room temperature. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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21 pages, 3592 KiB

Open AccessArticle

Nickel Supported on AlCeO₃ as a Highly Selective and Stable Catalyst for Hydrogen Production via the Glycerol Steam Reforming Reaction

by Nikolaos D. Charisiou, Georgios I. Siakavelas, Binlin Dou, Victor Sebastian, Steven J. Hinder, Mark A. Baker, Kyriaki Polychronopoulou and Maria A. Goula

Catalysts 2019, 9(5), 411; https://doi.org/10.3390/catal9050411 - 1 May 2019

Cited by 44 | Viewed by 5314

Abstract

In this study, a critical comparison between two low metal (Ni) loading catalysts is presented, namely Ni/Al₂O₃ and Ni/AlCeO₃ for the glycerol steam reforming (GSR) reaction. The surface and bulk properties of the catalysts were evaluated using a plethora [...] Read more.

In this study, a critical comparison between two low metal (Ni) loading catalysts is presented, namely Ni/Al₂O₃ and Ni/AlCeO₃ for the glycerol steam reforming (GSR) reaction. The surface and bulk properties of the catalysts were evaluated using a plethora of techniques, such as N₂ adsorption/desorption, Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP–AES), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy / Energy Dispersive X-Ray Spectroscopy (SEM/EDX, Transmission Electron Microscopy (TEM), CO₂ and NH₃– Temperature Programmed Desorption (TPD), and Temperature Programmed Reduction (H₂–TPR). Carbon deposited on the catalyst’s surfaces was probed using Temperature Programmed Oxidation (TPO), SEM, and TEM. It is demonstrated that Ce-modification of Al₂O₃ induces an increase of the surface basicity and Ni dispersion. These features lead to a higher conversion of glycerol to gaseous products (60% to 80%), particularly H₂ and CO₂, enhancement of WGS reaction, and a higher resistance to coke deposition. Allyl alcohol was found to be the main liquid product for the Ni/AlCeO₃ catalyst, the production of which ceases over 700 °C. It is also highly significant that the Ni/AlCeO₃ catalyst demonstrated stable values for H₂ yield (2.9–2.3) and selectivity (89–81%), in addition to CO₂ (75–67%) and CO (23–29%) selectivity during a (20 h) long time-on-stream study. Following the reaction, SEM/EDX and TEM analysis showed heavy coke deposition over the Ni/Al₂O₃ catalyst, whereas for the Ni/AlCeO₃ catalyst TPO studies showed the formation of more defective coke, the latter being more easily oxidized. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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15 pages, 9692 KiB

Open AccessArticle

Highly Dispersed Ni Nanocatalysts Derived from NiMnAl-Hydrotalcites as High-Performing Catalyst for Low-Temperature Syngas Methanation

by Bin Lu, Jiahao Zhuang, Jinping Du, Fangna Gu, Guangwen Xu, Ziyi Zhong, Qing Liu and Fabing Su

Catalysts 2019, 9(3), 282; https://doi.org/10.3390/catal9030282 - 19 Mar 2019

Cited by 16 | Viewed by 4794

Abstract

Increasing the low-temperature performance of nickel-based catalysts in syngas methanation is critical but very challenging, because at low temperatures there is high concentration of CO on the catalyst surface, causing formation of nickel carbonyl with metallic Ni and further catalyst deactivation. Herein, we [...] Read more.

Increasing the low-temperature performance of nickel-based catalysts in syngas methanation is critical but very challenging, because at low temperatures there is high concentration of CO on the catalyst surface, causing formation of nickel carbonyl with metallic Ni and further catalyst deactivation. Herein, we have prepared highly dispersed Ni nanocatalysts by in situ reduction of NiMnAl-layered double hydroxides (NiMnAl-LDHs) and applied them to syngas methanation. The synthesized Ni nanocatalysts maintained the nanosheet structure of the LDHs, in which Ni particles were decorated with MnO_y species and embedded in the AlO_x nanosheets. It was observed that the Ni nanocatalysts exhibited markedly better low-temperature performance than commercial catalysts in the syngas methanation. At 250 °C, 3.0 MPa and a high weight hourly space velocity (WHSV) of 30,000 mL·g⁻¹·h⁻¹, both the CO conversion and the CH₄ selectivity reached 100% over the former, while those over the commercial catalyst were only 14% and 76%, respectively. Furthermore, this NiMnAl catalyst exhibited strong anti-carbon and anti-sintering properties at high temperatures. The enhanced low-temperature performance and high-temperature stability originated from the promotion effect of MnO_y and the embedding effect of AlO_x in the catalyst. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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12 pages, 3154 KiB

Open AccessArticle

The Role of NiO in Reactive Adsorption Desulfurization Over NiO/ZnO-Al₂O₃-SiO₂ Adsorbent

by Feng Ju, Miao Wang, Tian Wu and Hao Ling

Catalysts 2019, 9(1), 79; https://doi.org/10.3390/catal9010079 - 14 Jan 2019

Cited by 18 | Viewed by 5088

Abstract

The reactive adsorption desulfurization (RADS) of a model gasoline n-hexane containing thiophene was carried out with a NiO/ZnO-Al₂O₃-SiO₂ adsorbent in N₂ and H₂, respectively. A declining RADS trend has been observed in N₂ [...] Read more.

The reactive adsorption desulfurization (RADS) of a model gasoline n-hexane containing thiophene was carried out with a NiO/ZnO-Al₂O₃-SiO₂ adsorbent in N₂ and H₂, respectively. A declining RADS trend has been observed in N₂, without the presence of H₂, indicating that NiO is sulfurized and exhibits activity for RADS. TPR and XPS results presented NiO in the adsorbent is hard to be reduced because of the powerful interaction between NiO and the support. The sulfurization of NiO into NiSx is a primary condition for the RADS process, the same as the presulfurization of hydrotreating catalyst, while metallic Ni is an intermediate reduction product of NiSx. Results of a low RADS temperature at 300 °C, much lower than the reduction temperature of NiO, suggest that NiO plays an important role. Based on assumption of NiO as the main active component, the RADS could reduce the reaction temperature and energy consumption significantly. The participation of hydrogen and n-hexane in pretreatment conducted at 420 °C contributes to the activation of adsorbent. Also, these methods of pretreatment improved the desulfurization performance under the reaction temperature of 300 °C. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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7 pages, 816 KiB

Open AccessArticle

Prominent Conductor Mechanism-Induced Electron Transfer of Biochar Produced by Pyrolysis of Nickel-Enriched Biomass

by Wenbing Tan, Renfei Li, Hanxia Yu, Xinyu Zhao, Qiuling Dang, Jie Jiang, Lei Wang and Beidou Xi

Catalysts 2018, 8(12), 573; https://doi.org/10.3390/catal8120573 - 22 Nov 2018

Cited by 4 | Viewed by 3359

Abstract

Biochar is redox-active and can function as a sustainable electron shuttle in catalyzing relevant redox reactions. It plays a crucial role in environmental remediation. In this work, we used different-nickel (Ni)-level biochars produced by the pyrolysis of plant biomass with correspondingly different Ni [...] Read more.

Biochar is redox-active and can function as a sustainable electron shuttle in catalyzing relevant redox reactions. It plays a crucial role in environmental remediation. In this work, we used different-nickel (Ni)-level biochars produced by the pyrolysis of plant biomass with correspondingly different Ni levels as extracellular electron shuttles for microbial reduction of ferrihydrite by Shewanella oneidensis MR-1. A high Ni level of the precursor considerably enhanced the conductor mechanism of the produced biochar and thus enabled the biochar to catalyze increased microbial reductions of the Fe(III) mineral, but it did not promote the charging and discharging capacities of the produced biochar. This study can aid in the search for natural biomass with high Ni content to establish low-cost biochars with wide-ranging applications in catalyzing the redox-mediated reactions of pollutants. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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10 pages, 8911 KiB

Open AccessArticle

Application of POCOP Pincer Nickel Complexes to the Catalytic Hydroboration of Carbon Dioxide

by Jie Zhang, Jiarui Chang, Ting Liu, Bula Cao, Yazhou Ding and Xuenian Chen

Catalysts 2018, 8(11), 508; https://doi.org/10.3390/catal8110508 - 1 Nov 2018

Cited by 26 | Viewed by 4413

Abstract

The reduction of CO₂ is of great importance. In this paper, different types of bis(phosphinite) (POCOP) pincer nickel complexes, [2,6-(R₂PO)₂C₆H₃]NiX (R = ^tBu, ⁱPr, Ph; X = SH, N₃, NCS), [...] Read more.

The reduction of CO₂ is of great importance. In this paper, different types of bis(phosphinite) (POCOP) pincer nickel complexes, [2,6-(R₂PO)₂C₆H₃]NiX (R = ^tBu, ⁱPr, Ph; X = SH, N₃, NCS), were applied to the catalytic hydroboration of CO₂ with catecholborane (HBcat). It was found that pincer complexes with ^tBu₂P or ⁱPr₂P phosphine arms are active catalysts for this reaction in which CO₂ was successfully reduced to a methanol derivative (CH₃OBcat) with a maximum turnover frequency of 1908 h⁻¹ at room temperature under an atmospheric pressure of CO₂. However, complexes with phenyl-substituted phosphine arms failed to catalyze this reaction—the catalysts decomposed under the catalytic conditions. Complexes with ⁱPr₂P phosphine arms are more active catalysts compared with the corresponding complexes with ^tBu₂P phosphine arms. For complexes with the same phosphine arms, the catalytic activity follows the series of mercapto complex (X = SH) ≈ azido complex (X = N₃) >> isothiocyanato complex (X = NCS). It is believed that all of these catalytic active complexes are catalyst precursors which generate the nickel hydride complex [2,6-(R₂PO)₂C₆H₃]NiH in situ, and the nickel hydride complex is the active species to catalyze this reaction. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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9 pages, 4343 KiB

Open AccessArticle

Study of Chemical and Morphological Transformations during Ni₂Mo₃N Synthesis via an Oxide Precursor Nitration Route

by Denis V. Leybo, Dmitry I. Arkhipov, Konstantin L. Firestein and Denis V. Kuznetsov

Catalysts 2018, 8(10), 436; https://doi.org/10.3390/catal8100436 - 3 Oct 2018

Cited by 3 | Viewed by 2899

Abstract

Chemical and morphological transformations during Ni₂Mo₃N synthesis were studied in this work. Nitride samples were synthesized from oxide precursors in H₂/N₂ flow and were analyzed by thermogravimetry, X-ray diffraction analysis, scanning electron microscopy, and energy dispersive [...] Read more.

Chemical and morphological transformations during Ni₂Mo₃N synthesis were studied in this work. Nitride samples were synthesized from oxide precursors in H₂/N₂ flow and were analyzed by thermogravimetry, X-ray diffraction analysis, scanning electron microscopy, and energy dispersive X-ray spectroscopy methods. In addition, physical and chemical adsorption properties were studied using low-temperature N₂ physisorption and NH₃ temperature-programmed desorption. It was shown that nitride formation proceeds through a sequence of phase transformations: NiMoO₄ + MoO₃ → Ni + NiMo + MoO₂ → Ni + NiMo + Mo₂N → Ni₂Mo₃N. The weight changes that were calculated from the proposed reactions were in agreement with the experimental data from thermogravimetry. The morphology of the powder changed from platelets and spheres for the oxide sample, to aggregates of needle-like particles for the intermediate product, to porous particles with an extended surface area for the nitride final product. The obtained results should prove useful for subsequent Ni₂Mo₃N based catalysts production process optimization. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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12 pages, 4825 KiB

Open AccessArticle

NO_x Removal by Selective Catalytic Reduction with Ammonia over a Hydrotalcite-Derived NiFe Mixed Oxide

by Ruonan Wang, Xu Wu, Chunlei Zou, Xiaojian Li and Yali Du

Catalysts 2018, 8(9), 384; https://doi.org/10.3390/catal8090384 - 8 Sep 2018

Cited by 42 | Viewed by 5488

Abstract

A series of NiFe mixed oxide catalysts were prepared via calcining hydrotalcite-like precursors for the selective catalytic reduction of nitrogen oxides (NO_x) with NH₃ (NH₃-SCR). Multiple characterizations revealed that catalytic performance was highly dependent on the phase composition, [...] Read more.

A series of NiFe mixed oxide catalysts were prepared via calcining hydrotalcite-like precursors for the selective catalytic reduction of nitrogen oxides (NO_x) with NH₃ (NH₃-SCR). Multiple characterizations revealed that catalytic performance was highly dependent on the phase composition, which was vulnerable to the calcination temperature. The MO_x phase (M = Ni or Fe) formed at a lower calcination temperature would induce more favorable contents of Fe²⁺ and Ni³⁺ and as a result contribute to the better redox capacity and low-temperature activity. In comparison, NiFe₂O₄ phase emerged at a higher calcination temperature, which was expected to generate more Fe species on the surface and lead to a stable structure, better high-temperature activity, preferable SO₂ resistance, and catalytic stability. The optimum NiFe-500 catalyst incorporated the above virtues and afforded excellent denitration (DeNO_x) activity (over 85% NO_x conversion with nearly 98% N₂ selectivity in the region of 210–360 °C), superior SO₂ resistance, and catalytic stability. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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12 pages, 4718 KiB

Open AccessArticle

Highly Loaded and Dispersed Ni₂P/Al₂O₃ Catalyst with High Selectivity for Hydrogenation of Acetophenone

by Junen Wang, Yanling Wang, Gaoli Chen and Zhanjun He

Catalysts 2018, 8(8), 309; https://doi.org/10.3390/catal8080309 - 30 Jul 2018

Cited by 12 | Viewed by 5016

Abstract

Highly loaded and dispersed Ni₂P/Al₂O₃ catalyst was prepared by the phosphidation of Ni/Al₂O₃ catalyst with Ni loading of 80 wt.% in liquid phase and compared with the Ni/Al₂O₃ catalyst for the hydrogenation [...] Read more.

Highly loaded and dispersed Ni₂P/Al₂O₃ catalyst was prepared by the phosphidation of Ni/Al₂O₃ catalyst with Ni loading of 80 wt.% in liquid phase and compared with the Ni/Al₂O₃ catalyst for the hydrogenation of acetophenone. X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) etc. were used to characterize the textural and structural properties of the prepared catalysts. It was found that the Ni/Al₂O₃ and Ni₂P/Al₂O₃ catalyst possessed high surface area, loading and dispersion. The Ni/Al₂O₃ catalyst had higher apparent activity while the Ni₂P/Al₂O₃ catalyst had higher intrinsic activity for the hydrogenation of acetophenone (AP). Remarkably, the Ni₂P/Al₂O₃ catalyst exhibited high selectivity to 1-phenylethanol, due to repulsion of the phosphorous (P^{$δ$ −}) for phenyl group and attraction of the nickel (Ni^{$δ$ +}) for oxygen atom of carbonyl group, leading to preferential hydrogenation of carbonyl group in acetophenone. The effect of the particle size of the catalyst on the chemical selectivity might be another reason for high selectivity on the Ni₂P/Al₂O₃ catalyst. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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Review

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39 pages, 6965 KiB

Open AccessReview

Lignin Valorizations with Ni Catalysts for Renewable Chemicals and Fuels Productions

by Xiao Chen, Weixiang Guan, Chi-Wing Tsang, Haoquan Hu and Changhai Liang

Catalysts 2019, 9(6), 488; https://doi.org/10.3390/catal9060488 - 28 May 2019

Cited by 46 | Viewed by 8788

Abstract

Energy and fuels derived from biomass pose lesser impact on the environmental carbon footprint than those derived from fossil fuels. In order for the biomass-to-energy and biomass-to-chemicals processes to play their important role in the loop of the circular economy, highly active, selective, [...] Read more.

Energy and fuels derived from biomass pose lesser impact on the environmental carbon footprint than those derived from fossil fuels. In order for the biomass-to-energy and biomass-to-chemicals processes to play their important role in the loop of the circular economy, highly active, selective, and stable catalysts and the related efficient chemical processes are urgently needed. Lignin is the most thermal stable fraction of biomass and a particularly important resource for the production of chemicals and fuels. This mini review mainly focuses on lignin valorizations for renewable chemicals and fuels production and summarizes the recent interest in the lignin valorization over Ni and relevant bimetallic metal catalysts on various supports. Particular attention will be paid to those strategies to convert lignin to chemicals and fuels components, such as pyrolysis, hydrodeoxygenation, and hydrogenolysis. The review is written in a simple and elaborated way in order to draw chemists and engineers’ attention to Ni-based catalysts in lignin valorizations and guide them in designing innovative catalytic materials based on the lignin conversion reaction. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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27 pages, 10813 KiB

Open AccessFeature PaperReview

Ni Promotion by Fe: What Benefits for Catalytic Hydrogenation?

by Dichao Shi, Robert Wojcieszak, Sébastien Paul and Eric Marceau

Catalysts 2019, 9(5), 451; https://doi.org/10.3390/catal9050451 - 15 May 2019

Cited by 52 | Viewed by 12089

Abstract

Metallic nickel is known to efficiently catalyze hydrogenation reactions, but one of its major drawbacks lies in its lack of selectivity, linked to side-reactions of hydrogenolysis and over-hydrogenation. More selective hydrogenations can be obtained upon the introduction of a second metal in combination [...] Read more.

Metallic nickel is known to efficiently catalyze hydrogenation reactions, but one of its major drawbacks lies in its lack of selectivity, linked to side-reactions of hydrogenolysis and over-hydrogenation. More selective hydrogenations can be obtained upon the introduction of a second metal in combination with Ni. Fe is an interesting choice, as it is a cheap and abundant metal. This review aims at discussing the advantages and constraints brought by the preparation procedures of bimetallic supported Ni–Fe nanoparticles, and at analyzing the benefits one can draw by substituting Ni–Fe supported catalysts for Ni monometallic systems for the catalytic hydrogenation of organic molecules. Specific formulations, such as Ni₇₅Fe₂₅, will be singled out for their high activity or selectivity, and the various hypotheses behind the roles played by Fe will be summarized. Full article

(This article belongs to the Special Issue Ni-Containing Catalysts)

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