Special Issue "Noble Metal Catalysts"

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

Deadline for manuscript submissions: closed (31 October 2020) | Viewed by 9029

Special Issue Editors

Prof. Dr. Ioannis V. Yentekakis
E-Mail Website
Guest Editor
Physical Chemistry and Chemical Processes Laboratory, School of Environmental Engineering, Technical University of Crete (TUC), 73100 Chania, Greece
Interests: nanomaterials and nanotechnology; heterogeneous nano-catalysis; environmental catalysis (NOx, N2O; CO, CH4, VOCs, H2S and SO2 emissions control); catalysts’ promotion; electrochemical promotion; surfaces and interfaces; electrochemistry; fuel cells; CO2 utilization; biogas and natural gas valorization
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Georgios Kyriakou
E-Mail Website
Guest Editor
Department of Chemical Engineering, University of Patras, Patras, Greece
Interests: heterogeneous catalysis; photocatalysis; chiral networks; self-assembled systems; sensor technology; electrochemistry

Special Issue Information

Dear Colleagues,

Noble metals (NMs), i.e., ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), osmium (Os), Iridium (Ir) platinum (Pt) and gold (Au), receive a great deal of research interest due to their remarkable, and in many cases unique, performances in numerous catalytic reaction systems, embracing both industrial reactions for the large-scale synthesis of commodity chemicals of global importance, as well as reactions that play a critical role in environmental protection and energy generation systems. A short list of NM-catalyzed reactions of great importance includes:

  • Emissions control catalysis, such as CO or hydrocarbon oxidations, NOx (NO+NO2) reduction in three-way catalysts under rich or lean conditions, and N2O abatement in the absence or presence of excess oxygen;
  • Steam-, dry (CO2)- or multireforming reactions for syngas and/or hydrogen production, implementations in which the high activity of noble metals is accompanied by their typical very low propensity for carbon formation/accumulation—the main problem responsible for reforming catalysts deactivation;
  • H2 electro-oxidation for electrical power production in low-to-intermediate temperature proton-exchange membrane fuel cells (PEM-FCs);
  • Water oxidation electrocatalysis (i.e., oxygen or hydrogen evolution reaction, HER/OER) that has received much attention in the last few years because of its prime role in water splitting, rechargeable metal–air batteries and fuel cells for electrical power generation;
  • Olefins epoxidation, asymmetric hydrogenation, transfer hydrogenation, allylic substitution, and C–H borylation reactions for the synthesis of natural products, and so on.

Heterogeneous catalytic applications which utilize noble metals are currently receiving renewed interest as a result of ongoing progress in nanotechnology and catalysts promotion strategies that provide efficient ways to fine-tune the surface morphology and electronic properties of metal nanoparticles, thus further enhancing their catalytic activity and also their time-on-stream stability, even at high temperatures. Advanced synthesis methods provide means for the production of highly dispersed, up to atomic level, noble metal particles on active supports, maximizing the population of active centers and enhancing beneficial metal–support interactions, resulting in cost-effective high performance and robust catalytic materials.              

This Special Issue aims to cover recent research progress, both theoretical and experimental, in the field of catalysis by noble metals. Advanced synthesis routes, physicochemical–textural–structural characterization of NM-based catalytic materials, activity–selectivity–durability evaluation under the titled reactions, fundamental understanding of structure–activity relationships or other metal–metal and metal–support interactions on multifunctional noble metal catalysts, as well as computational studies (e.g., DFT calculations), catalytic reaction mechanisms, and processes are very welcome.

Prof. Dr. Ioannis V. Yentekakis
Prof. Dr. Georgios Kyriakou
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 2200 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

  • Catalysis by noble metals 
  • Noble metal electrocatalysis 
  • Nano-structured noble metal catalysts 
  • Au-based catalysts 
  • Platinum group metal catalysts 
  • Advanced synthesis routes of NM-catalysts 
  • Structural textural physicochemical characterizations of NM nanocatalysts 
  • NM-catalysts promotion
  • Metal–metal and metal–support interactions 
  • Noble metal catalysts for energy applications 
  • Emissions control catalysis by NMs 
  • Methane reforming by noble metals 
  • Olefins epoxidation 
  • Noble metal-based electrodes and fuel cells

Published Papers (5 papers)

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Research

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Article
One-Step Fabrication of PtSn/γ-Al2O3 Catalysts with La Post-Modification for Propane Dehydrogenation
Catalysts 2020, 10(9), 1042; https://doi.org/10.3390/catal10091042 - 10 Sep 2020
Cited by 1 | Viewed by 1045
Abstract
The catalytic dehydrogenation of propane to propene is an alternative technique to supplement the traditional steam cracking and catalytic cracking process for satisfying the continuously increasing demand for propylene downstream products. In this study, the parent PtSn/γ-Al2O3 catalyst was fabricated [...] Read more.
The catalytic dehydrogenation of propane to propene is an alternative technique to supplement the traditional steam cracking and catalytic cracking process for satisfying the continuously increasing demand for propylene downstream products. In this study, the parent PtSn/γ-Al2O3 catalyst was fabricated via the one-step method for the subsequent La post-modification to prepare the catalysts for propane dehydrogenation. The prepared and spent catalysts were characterized by X-ray diffraction (XRD), N2 adsorption–desorption, scanning electron microscope (SEM), NH3 temperature-programmed desorption (NH3-TPD), H2 temperature-programmed desorption (H2-TPR), and thermogravimetric (TG) analysis. The catalytic performance and characterization results demonstrated that the addition of La into the parent catalyst could significantly improve the catalytic performance of the prepared catalyst. Especially, the PtSn-La2.2 catalyst with the 2.2 wt.% La addition exhibited the stable and highest propylene selectivity (>84%) under the investigation time of 800 min. The introduced La exhibits the ability to adjust the textural properties of the obtained catalysts, curb the acidity of support, promote the reduction of Pt species, and reduce the carbon accumulation on the prepared catalysts. Full article
(This article belongs to the Special Issue Noble Metal Catalysts)
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Article
Asymmetric Hydrogenation of 1-aryl substituted-3,4-Dihydroisoquinolines with Iridium Catalysts Bearing Different Phosphorus-Based Ligands
Catalysts 2020, 10(8), 914; https://doi.org/10.3390/catal10080914 - 10 Aug 2020
Cited by 2 | Viewed by 1333
Abstract
Starting from the chiral 5,6,7,8-tetrahydroquinolin-8-ol core, a series of amino-phosphorus-based ligands was realized. The so-obtained amino-phosphine ligand (L1), amino-phosphinite (L2) and amino-phosphite (L3) were evaluated in iridium complexes together with the heterobiaryl diphosphines tetraMe-BITIOP (L4), [...] Read more.
Starting from the chiral 5,6,7,8-tetrahydroquinolin-8-ol core, a series of amino-phosphorus-based ligands was realized. The so-obtained amino-phosphine ligand (L1), amino-phosphinite (L2) and amino-phosphite (L3) were evaluated in iridium complexes together with the heterobiaryl diphosphines tetraMe-BITIOP (L4), Diophep (L5) and L6 and L7 ligands, characterized by mixed chirality. Their catalytic performance in the asymmetric hydrogenation (AH) of the model substrate 6,7-dimethoxy-1-phenyl-3,4-dihydroisoquinoline 1a led us to identify Ir-L4 and Ir-L5 catalysts as the most effective. The application of these catalytic systems to a library of differently substituted 1-aryl-3,4-dihydroisoquinolines afforded the corresponding products with variable enantioselective levels. The 4-nitrophenyl derivative 3b was obtained in a complete conversion and with an excellent 94% e.e. using Ir-L4, and a good 76% e.e. was achieved in the reduction of 2-nitrophenyl derivative 6a using Ir-L5. Full article
(This article belongs to the Special Issue Noble Metal Catalysts)
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Article
Hydrothermal Aging of Pd/LTA Monolithic Catalyst for Complete CH4 Oxidation
Catalysts 2020, 10(5), 517; https://doi.org/10.3390/catal10050517 - 07 May 2020
Cited by 6 | Viewed by 1135
Abstract
Palladium-based catalysts are known to provide high CH4 oxidation activity. One drawback for these materials is that they often lose activity in the presence of water vapor due to the formation of surface hydroxyls. It is however possible to improve the water [...] Read more.
Palladium-based catalysts are known to provide high CH4 oxidation activity. One drawback for these materials is that they often lose activity in the presence of water vapor due to the formation of surface hydroxyls. It is however possible to improve the water vapor tolerance by using zeolites as support material. In this study, we have investigated Pd supported on thermally stable LTA zeolite with high framework Si/Al ratio (Si/Al = ~44) for CH4 oxidation and the effect of hydrothermal aging at temperatures up to 900 °C. High and stable CH4 oxidation activity in the presence of water vapor was observed for Pd/LTA after hydrothermal aging at temperatures ≤ 700 °C. However, aging at temperatures of 800–900 °C resulted in catalyst deactivation. This deactivation was not a result of structural collapse of the LTA zeolite as the LTA zeolite only showed minor changes in surface area, pore volume, and X-ray diffraction pattern after 900 °C aging. We suggest that the deactivation was caused by extensive formation of ion-exchanged Pd2+ together with Pd sintering. These two types of Pd species appear to have lower CH4 oxidation activity and to be more sensitive to water deactivation compared to the well dispersed Pd particles observed on the LTA support prior to the hydrothermal aging. By contrast, Pd/Al2O3 was generally sensitive to water vapor no matter of the aging temperature. Although the aging caused extensive Pd sintering in Pd/Al2O3, only minor deterioration of the CH4 oxidation activity was seen. The results herein presented show that Pd/LTA is a promising CH4 oxidation catalyst, however Pd rearrangement at high temperatures (≥800 °C) is one remaining challenge. Full article
(This article belongs to the Special Issue Noble Metal Catalysts)
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Review

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Review
Pt-Ni Nanoalloys for H2 Generation from Hydrous Hydrazine
Catalysts 2020, 10(8), 930; https://doi.org/10.3390/catal10080930 - 13 Aug 2020
Cited by 5 | Viewed by 1142
Abstract
Hydrous hydrazine (N2H4∙H2O) is a candidate for a hydrogen carrier for storage and transportation due to low material cost, high hydrogen content of 8.0%, and liquid stability at room temperature. Pt and Pt nanoalloy catalysts have been [...] Read more.
Hydrous hydrazine (N2H4∙H2O) is a candidate for a hydrogen carrier for storage and transportation due to low material cost, high hydrogen content of 8.0%, and liquid stability at room temperature. Pt and Pt nanoalloy catalysts have been welcomed by researchers for the dehydrogenation of hydrous hydrazine recently. Therefore, in this review, we give a summary of Pt nanoalloy catalysts for the dehydrogenation of hydrous hydrazine and briefly introduce the decomposition mechanism of hydrous hydrazine to prove the design principle of the catalyst. The chemical characteristics of hydrous hydrazine and the mechanism of dehydrogenation reaction are briefly introduced. The catalytic activity of hydrous hydrazine on different supports and the factors affecting the selectivity of hydrogen catalyzed by Ni-Pt are analyzed. It is expected to provide a new way for the development of high-activity catalysts for the dehydrogenation of hydrous hydrazine to produce hydrogen. Full article
(This article belongs to the Special Issue Noble Metal Catalysts)
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Review
Recent Organic Transformations with Silver Carbonate as a Key External Base and Oxidant
Catalysts 2019, 9(12), 1032; https://doi.org/10.3390/catal9121032 - 06 Dec 2019
Cited by 7 | Viewed by 2283
Abstract
Silver carbonate (Ag2CO3), a common transition metal-based inorganic carbonate, is widely utilized in palladium-catalyzed C–H activations as an oxidant in the redox cycle. Silver carbonate can also act as an external base in the reaction medium, especially in organic [...] Read more.
Silver carbonate (Ag2CO3), a common transition metal-based inorganic carbonate, is widely utilized in palladium-catalyzed C–H activations as an oxidant in the redox cycle. Silver carbonate can also act as an external base in the reaction medium, especially in organic solvents with acidic protons. Its superior alkynophilicity and basicity make silver carbonate an ideal catalyst for organic reactions with alkynes, carboxylic acids, and related compounds. This review describes recent reports of silver carbonate-catalyzed and silver carbonate-mediated organic transformations, including cyclizations, cross-couplings, and decarboxylations. Full article
(This article belongs to the Special Issue Noble Metal Catalysts)
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