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Catalysts
Special Issues
Characterization Analysis of Heterogeneous Catalysts
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Characterization Analysis of Heterogeneous Catalysts

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Catalytic Materials".

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 25939

Special Issue Editors

Dr. Anna B. Kroner

E-Mail Website
Guest Editor
Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
Interests: X-ray absorption spectroscopy;development of sample environments for operando studies; Fischer–Tropsch catalysts; three-way catalysis; methane dehydroaromatisation; selective catalytic reduction of NOx by NH3; CO oxidation; NH3 oxidation
Dr. Diego Gianolio

E-Mail Website
Guest Editor
Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
Interests: X-ray absorption spectroscopy; heterogeneous catalysis for selective oxidation; effect of promoters and doping; operando XAS characterization; metal nanoparticles; metal organic frameworks; transition metal complexes; anticancer drugs; photochemistry; electrochemistry; CO2 reduction reaction; oxygen evolution reaction

Special Issue Information

Dear Colleagues,

Heterogeneous catalysis is essential to chemical industries, wherein nearly 90% of chemicals are facilitated by heterogeneous catalysts. Thus, high selectivity and activity of catalysts are among the most crucial requirements for a successful commercial application. Firstly, finding relationships between structure and activity is a main challenge in fundamental and applied catalysis research owing to the complex structures displayed by heterogeneous catalysts. Another major problem related to the operation of heterogeneous catalysis is the loss of catalyst activity with time-on-stream which refers to deactivation. The catalyst deactivation is likely to occur through poisoning of catalyst-active phase, sintering of the catalyst and blockage of the active sites. This process is inevitable, but it can be slowed or prevented, and some of its consequences can be avoided.

It is well known from ex situ structural characterisation that the morphology, composition and crystalline structure of the catalysts evolve during catalytic reactions. Undoubtedly, significant progress has been made in using advanced synchrotron and neutron scattering-based characterisation methods. However, taking into account that the metal active site loading in the sample is often only a few percentage points, the measured signal mainly originates from the bulk volume and not from the surface where the reaction takes place. Thus, gaining new knowledge on the catalyst structure of active sites, interactions of adsorbates on supported catalyst and the catalyst deactivation process is crucial to design more efficient and robust catalytic materials. This cannot be achieved using a single technique and combined approach of various methods needs to be applied to provide a full picture of heterogeneous materials and their processes.

Therefore, this Special Issue primarily focuses on the comprehensive and fundamental off-line characterisation, neutron scattering and synchrotron-based X-ray techniques that play a key role in obtaining insight information on heterogeneous catalysts, their interactions with the reactants, catalyst deactivation and understanding the structure-function-reactivity relationship for a range of catalytic processes.

Dr. Anna B. Kroner
Dr. Diego Gianolio
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Catalysts is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • X-ray spectroscopy (XAS, XPS, XES)
  • Vibrational spectroscopy: FTIR and Raman
  • Neutron scattering
  • X-ray diffraction (XRD)
  • Electron microscopy
  • NMR
  • Structural characterisation
  • Operando studies
  • Three-way catalysis
  • Fischer–Tropsch catalysis
  • Selective oxidation
  • Catalyst deactivation
  • Effect of promoters and doping
  • Metal nanoparticles
  • Metal organic framework
  • Electrochemistry
  • Zeolites
  • Biomass

Published Papers (10 papers)

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Research

13 pages, 8820 KiB  
Article
Magnetically Reusable Fe3O4@NC@Pt Catalyst for Selective Reduction of Nitroarenes
by Jun Qiao, Tian Wang, Kai Zheng, Enmu Zhou, Chao Shen, Aiquan Jia and Qianfeng Zhang
Catalysts 2021, 11(10), 1219; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11101219 - 09 Oct 2021
Cited by 7 | Viewed by 1671
Abstract
A novel reusable Fe3O4@NC@Pt heterogeneous catalyst was synthesized by immobilizing platinum on nitrogen-doped carbon magnetic nanostructures. It was characterized by infrared analysis (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The catalytic efficiency of [...] Read more.
A novel reusable Fe3O4@NC@Pt heterogeneous catalyst was synthesized by immobilizing platinum on nitrogen-doped carbon magnetic nanostructures. It was characterized by infrared analysis (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The catalytic efficiency of Fe3O4@NC@Pt was investigated by reduction of nitro aromatic compounds. The catalyst showed good catalytic activity, wide range of substrates, and good chemical selectivity, especially for the substrates of compounds containing halide and carbonyl groups. The magnetically catalyst can readily be reused up to ten cycles without loss of catalytic activity. Moreover, the key pharmaceutical intermediate Lorlatini can be facilely achieved through this strategy. Full article
(This article belongs to the Special Issue Characterization Analysis of Heterogeneous Catalysts)
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8 pages, 2850 KiB  
Article
Novel Recyclable Pd/H-MOR Catalyst for Suzuki-Miyaura Coupling and Application in the Synthesis of Crizotinib
by Enmu Zhou, Jianzhong Jin, Kai Zheng, Letian Zhang, Hao Xu and Chao Shen
Catalysts 2021, 11(10), 1213; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11101213 - 09 Oct 2021
Cited by 5 | Viewed by 1810
Abstract
In this paper, we report an effective ultrasound method for the synthesis of Pd/H-MOR, which was used as a catalyst in the Suzuki-Miyaura coupling of aryl halides with phenylboronic acid. The structure and morphology of the as-prepared catalysts were fully characterized by X-ray [...] Read more.
In this paper, we report an effective ultrasound method for the synthesis of Pd/H-MOR, which was used as a catalyst in the Suzuki-Miyaura coupling of aryl halides with phenylboronic acid. The structure and morphology of the as-prepared catalysts were fully characterized by X-ray diffraction (XRD), N2 sorption isotherms, scanning electron microscopy (SEM), and an inductively coupled plasma-atomic emission spectrometer (ICP-AES). The advantages of Pd/H-MOR in the coupling reaction are green solvents, high yields, absence of ligands, and recyclability. The catalysts were easily reused at least ten times without significant deterioration in catalytic activity. In addition, this protocol was used in the marketed anti-tumor drug crizotinib synthesis. Full article
(This article belongs to the Special Issue Characterization Analysis of Heterogeneous Catalysts)
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Graphical abstract

12 pages, 2958 KiB  
Article
Non-Solvent Synthesis of a Robust Potassium-Doped PdCu-Pd-Cu@C Nanocatalyst for High Selectively Tandem Reactions
by Sanha Jang, Dicky Annas, Sehwan Song, Jong-Seong Bae, Sungkyun Park and Kang Hyun Park
Catalysts 2021, 11(10), 1191; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11101191 - 29 Sep 2021
Cited by 1 | Viewed by 1760
Abstract
A non-solvent synthesis of alkali metal-doped PdCu-Pd-Cu@C is presented that needs no mechanical grinding and utilizes heat treatment under an N2 gas flow. Pluronic® F127 is used to generate pores and a high surface area, and tannic acid is used as [...] Read more.
A non-solvent synthesis of alkali metal-doped PdCu-Pd-Cu@C is presented that needs no mechanical grinding and utilizes heat treatment under an N2 gas flow. Pluronic® F127 is used to generate pores and a high surface area, and tannic acid is used as a carbon source for the PdCu-Pd-Cu@C nanocatalysts. Because some C is transferred to organic compounds during the nitrogen heat treatment, this demonstrated the advantage of raising the weight ratio of active metals comparatively. The PdCu-Pd-Cu@C nanocatalyst developed in this study outperformed commercial Pd/C catalysts by bimetallic PdCu-Pd-Cu nanoparticles and Pd nanoparticles in terms of catalytic activity (selectivity of commercial Pd/C: 45%; PdCu-Pd-Cu@C nanocatalyst: 76%). The alkali metal dopants increase the selectivity of the final product on the PdCu-Pd-Cu@C surface because they are electron-rich, which assists in the adsorption of the substrate (selectivity of PdCu-Pd-Cu@C nanocatalyst: 76%; K-doped PdCu-Pd-Cu@C nanocatalysts: 90%). Furthermore, even after being reused 5 times in this research, the final catalytic performance was comparable to that of the initial catalyst. Full article
(This article belongs to the Special Issue Characterization Analysis of Heterogeneous Catalysts)
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24 pages, 5429 KiB  
Article
Unraveling Structural Details in Ga-Pd SCALMS Systems Using Correlative Nano-CT, 360° Electron Tomography and Analytical TEM
by Janis Wirth, Silvan Englisch, Dominik Drobek, Benjamin Apeleo Zubiri, Mingjian Wu, Nicola Taccardi, Narayanan Raman, Peter Wasserscheid and Erdmann Spiecker
Catalysts 2021, 11(7), 810; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11070810 - 01 Jul 2021
Cited by 8 | Viewed by 3210
Abstract
We present a comprehensive structural and analytical characterization of the highly promising supported catalytically active liquid metal solutions (SCALMS) system. This novel catalyst shows excellent performance for alkane dehydrogenation, especially in terms of resistance to coking. SCALMS consists of a porous support containing [...] Read more.
We present a comprehensive structural and analytical characterization of the highly promising supported catalytically active liquid metal solutions (SCALMS) system. This novel catalyst shows excellent performance for alkane dehydrogenation, especially in terms of resistance to coking. SCALMS consists of a porous support containing catalytically active low-melting alloy particles (e.g., Ga-Pd) featuring a complex structure, which are liquid at reaction temperature. High-resolution 3D characterization at various length scales is required to reveal the complex pore morphology and catalytically active sites’ location. Nano X-ray computed tomography (nano-CT) in combination with electron tomography (ET) enables nondestructive and scale-bridging 3D materials research. We developed and applied a correlative approach using nano-CT, 360°-ET and analytical transmission electron microscopy (TEM) to decipher the morphology, distribution and chemical composition of the Ga-Pd droplets of the SCALMS system over several length scales. Utilizing ET-based segmentations of nano-CT reconstructions, we are able to reliably reveal the homogenous porous support network with embedded Ga-Pd droplets featuring a nonhomogenous elemental distribution of Ga and Pd. In contrast, large Ga-Pd droplets with a high Ga/Pd ratio are located on the surface of SCALMS primary particles, whereas the droplet size and the Ga/Pd ratio decreases while advancing into the porous volume. Our studies reveal new findings about the complex structure of SCALMS which are required to understand its superior catalytic performance. Furthermore, advancements in lab-based nano-CT imaging are presented by extending the field of view (FOV) of a single experiment via a multiple region-of-interest (ROI) stitching approach. Full article
(This article belongs to the Special Issue Characterization Analysis of Heterogeneous Catalysts)
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17 pages, 2709 KiB  
Article
Promoting Effect of Copper Loading and Mesoporosity on Cu-MOR in the Carbonylation of Dimethyl Ether to Methyl Acetate
by Raju Poreddy, Susanne Mossin, Anker Degn Jensen and Anders Riisager
Catalysts 2021, 11(6), 696; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11060696 - 31 May 2021
Cited by 6 | Viewed by 2503
Abstract
Cu-mordenite (Cu-MOR) catalysts with different copper loadings were prepared, characterized and examined in continuous, gas-flow synthesis of methyl acetate (MA) by dimethyl ether (DME) carbonylation. Improved activity and selectivity were observed for Cu-MOR catalysts with up to 1 wt% Cu and X-ray photoelectron [...] Read more.
Cu-mordenite (Cu-MOR) catalysts with different copper loadings were prepared, characterized and examined in continuous, gas-flow synthesis of methyl acetate (MA) by dimethyl ether (DME) carbonylation. Improved activity and selectivity were observed for Cu-MOR catalysts with up to 1 wt% Cu and X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) spectroscopy and temperature-programmed reduction with hydrogen (H2-TPR) were used to elucidate the state of copper in the catalysts. Moreover, mesoporous MOR catalysts (RHMs) were prepared by mild stepwise recrystallization with X-ray powder diffraction (XRPD) and ammonia temperature-programmed desorption (NH3-TPD) demonstrating the retained MOR structure and the acid property of the catalysts, respectively. The RHM catalysts showed improved lifetime compared to pristine MOR giving a yield up to 78% MA with 93% selectivity after 5 h on stream (GHSV = 6711 h−1). Under identical reaction conditions, 1 wt% Cu-RHM catalysts had an even higher catalytic activity and durability resulting in a MA yield of 90% with 97% selectivity for 7–8 h of operation as well as a lower coke formation. Full article
(This article belongs to the Special Issue Characterization Analysis of Heterogeneous Catalysts)
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15 pages, 3155 KiB  
Article
Catalysis on Nanostructured Indium Tin Oxide Surface for Fast and Inexpensive Probing of Antibodies during Pandemics
by Arash Fattahi, Pooya Afaghi and Khashayar Ghandi
Catalysts 2021, 11(2), 191; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11020191 - 01 Feb 2021
Cited by 3 | Viewed by 2542
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global threat to human health and the economy. Society needs inexpensive, fast, and accurate quantitative diagnostic tools. Here, we report a new approach using a solid-state biosensor to measure antibodies, which does not [...] Read more.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global threat to human health and the economy. Society needs inexpensive, fast, and accurate quantitative diagnostic tools. Here, we report a new approach using a solid-state biosensor to measure antibodies, which does not require functionalization, unlike conventional biosensors. A nanostructured semiconductor surface with catalytic properties was used as a transducer for rapid immobilization and measurement of the antibody. The transducer response was based on solid-state electronics properties. The changes on the surface of the semiconductor induced changes in the direct current (DC) surface resistivity. This was a result of a catalytic chemical reaction on that surface. This new low-cost approach reduced the response time of the measurement significantly, and it required only a very small amount of sample on the microliter scale. Full article
(This article belongs to the Special Issue Characterization Analysis of Heterogeneous Catalysts)
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9 pages, 3315 KiB  
Article
Design and Characterization of Ag@Cu2O-rGO Nanocomposite for the p-Nitrophenol Reduction
by Chao Song, Shuang Guo and Lei Chen
Catalysts 2021, 11(1), 43; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11010043 - 31 Dec 2020
Cited by 4 | Viewed by 2922
Abstract
In this paper, we designed Ag nanoparticles coated with a Cu2O shell, which was successfully decorated on reduced graphene oxide (rGO) via a solid-state self-reduction. The Cu2O, Ag@Cu2O, and Ag@Cu2O-rGO nanocomposites were synthesized and characterized [...] Read more.
In this paper, we designed Ag nanoparticles coated with a Cu2O shell, which was successfully decorated on reduced graphene oxide (rGO) via a solid-state self-reduction. The Cu2O, Ag@Cu2O, and Ag@Cu2O-rGO nanocomposites were synthesized and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis, and XPS to evaluate the properties of the composites. In order to compare the chemical catalytic activity, the Cu2O, Ag@Cu2O, and Ag@Cu2O-rGO nanocomposites were employed for the catalytic reduction of p-nitrophenol (4-NP) into p-aminophenol (4-AP) in aqueous solution. The Ag@Cu2O-rGO nanocomposite exhibited excellent catalytic activity due to the intense interaction and high degree of electron transfer among Ag, Cu2O, and rGO. The rGO acted as the platform to bridge the isolated nanoparticles; furthermore, the electrons could quickly transfer from the Ag core to the Cu2O shell, which improved the chemical catalytic efficiency. Full article
(This article belongs to the Special Issue Characterization Analysis of Heterogeneous Catalysts)
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13 pages, 2116 KiB  
Article
Investigation of MoOx/Al2O3 under Cyclic Operation for Oxidative and Non-Oxidative Dehydrogenation of Propane
by Santhosh K. Matam, Caitlin Moffat, Pip Hellier, Michael Bowker, Ian P. Silverwood, C. Richard A. Catlow, S. David Jackson, James Craswell, Peter P. Wells, Stewart F. Parker and Emma K. Gibson
Catalysts 2020, 10(12), 1370; https://0-doi-org.brum.beds.ac.uk/10.3390/catal10121370 - 24 Nov 2020
Cited by 6 | Viewed by 2652
Abstract
A MoOx/Al2O3 catalyst was synthesised and tested for oxidative (ODP) and non-oxidative (DP) dehydrogenation of propane in a reaction cycle of ODP followed by DP and a second ODP run. Characterisation results show that the fresh catalyst contains [...] Read more.
A MoOx/Al2O3 catalyst was synthesised and tested for oxidative (ODP) and non-oxidative (DP) dehydrogenation of propane in a reaction cycle of ODP followed by DP and a second ODP run. Characterisation results show that the fresh catalyst contains highly dispersed Mo oxide species in the +6 oxidation state with tetrahedral coordination as [MoVIO4]2− moieties. In situ X-ray Absorption Spectroscopy (XAS) shows that [MoVIO4]2− is present during the first ODP run of the reaction cycle and is reduced to MoIVO2 in the following DP run. The reduced species are partly re-oxidised in the subsequent second ODP run of the reaction cycle. The partly re-oxidised species exhibit oxidation and coordination states that are lower than 6 but higher than 4 and are referred to as MoxOy. These species significantly improved propene formation (relatively 27% higher) in the second ODP run at similar propane conversion activity. Accordingly, the initial tetrahedral [MoVIO4]2− present during the first ODP run of the reaction cycle is active for propane conversion; however, it is unselective for propene. The reduced MoIVO2 species are relatively less active and selective for DP. It is suggested that the MoxOy species generated by the reaction cycle are active and selective for ODP. The vibrational spectroscopic data indicate that the retained surface species are amorphous carbon deposits with a higher proportion of aromatic/olefinic like species. Full article
(This article belongs to the Special Issue Characterization Analysis of Heterogeneous Catalysts)
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9 pages, 1875 KiB  
Article
The Interaction of Hydrogen with Iron Benzene-1,3,5-Tricarboxylate (Fe-BTC)
by Stewart F. Parker
Catalysts 2020, 10(11), 1255; https://0-doi-org.brum.beds.ac.uk/10.3390/catal10111255 - 30 Oct 2020
Cited by 2 | Viewed by 1666
Abstract
Inelastic neutron scattering (INS) spectroscopy is used to explore the 0–12,000 cm−1 range to characterise the interaction of H2 with iron benzene-1,3,5-tricarboxylate (Fe-BTC). Two peaks are observed in the low energy (<350 cm−1) region after exposure to H2 [...] Read more.
Inelastic neutron scattering (INS) spectroscopy is used to explore the 0–12,000 cm−1 range to characterise the interaction of H2 with iron benzene-1,3,5-tricarboxylate (Fe-BTC). Two peaks are observed in the low energy (<350 cm−1) region after exposure to H2. Measurements with hydrogen deuteride (HD) confirm that the peaks originate from H2. The most likely explanation is that there are two populations of H2 (HD) present. For both the H2- and the HD-loaded samples, the higher energy peak is close in energy to that of the pure isotopomer, so it is assigned to bulk-like H2/HD held in pores of the Fe-BTC. The lower energy peak is assigned to H2/HD interacting directly with the Fe ion exposed on dehydration. It was also possible to detect the H–H stretch in the same experiment; however, unfortunately, the instrumental resolution is insufficient to separate the stretch modes of the bound H2 (HD) and that in the pores. Full article
(This article belongs to the Special Issue Characterization Analysis of Heterogeneous Catalysts)
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16 pages, 6346 KiB  
Article
CO2 Methanation of Biogas over 20 wt% Ni-Mg-Al Catalyst: on the Effect of N2, CH4, and O2 on CO2 Conversion Rate
by Danbee Han, Yunji Kim, Hyunseung Byun, Wonjun Cho and Youngsoon Baek
Catalysts 2020, 10(10), 1201; https://0-doi-org.brum.beds.ac.uk/10.3390/catal10101201 - 16 Oct 2020
Cited by 22 | Viewed by 2899
Abstract
Biogas contains more than 40% CO2 that can be removed to produce high quality CH4. Recently, CH4 production from CO2 methanation has been reported in several studies. In this study, CO2 methanation of biogas was performed over [...] Read more.
Biogas contains more than 40% CO2 that can be removed to produce high quality CH4. Recently, CH4 production from CO2 methanation has been reported in several studies. In this study, CO2 methanation of biogas was performed over a 20 wt% Ni-Mg-Al catalyst, and the effects of CO2 conversion rate and CH4 selectivity were investigated as a function of CH4, O2, H2O, and N2 compositions of the biogas. At a gas hourly space velocity (GHSV) of 30,000 h−1, the CO2 conversion rate was ~79.3% with a CH4 selectivity of 95%. In addition, the effects of the reaction temperature (200–450 °C), GHSV (21,000–50,000 h−1), and H2/CO2 molar ratio (3–5) on the CO2 conversion rate and CH4 selectivity over the 20 wt% Ni-Mg-Al catalyst were evaluated. The characteristics of the catalyst were analyzed using Brunauer–Emmett–Teller surface area analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The catalyst was stable for approximately 200 h at a GHSV of 30,000 h−1 and a reaction temperature of 350 °C. CO2 conversion and CH4 selectivity were maintained at 75% and 93%, respectively, and the catalyst was therefore concluded to exhibit stable activity. Full article
(This article belongs to the Special Issue Characterization Analysis of Heterogeneous Catalysts)
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