Special Issue "Porous Materials: Active Phases or Supports in Heterogeneous Catalysis"

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

Deadline for manuscript submissions: closed (31 August 2022) | Viewed by 4569

Special Issue Editors

Prof. Dr. Angela Martins
E-Mail Website
Guest Editor
1. Department of Chemical Engineering, Instituto Superior de Engenharia de Lisboa, 1950-007, Lisboa, Portugal
2. Faculty of Sciences, University of Lisbon, 1749-016 Lisboa, Portugal
Interests: synthesis and modification of zeolite and hierarchical zeolites using conventional and innovative approaches; preparation of bifunctional catalysts using innovative methods to introduce metallic function; application of zeolites, hierarchical zeolites, and other porous materials such as carbons, clays, silicoaluminophosphates, and mesoporous silicas as active phases or supports to gas-phase refining and petrochemical reactions, such as cracking, hidroisomerization and alkylation as well as fine chemistry liquid phase reactions such as Friedel–Crafts acylation and oxidation reactions
Prof. Dr. Ana Paula Carvalho
E-Mail Website
Guest Editor
Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
Interests: synthesis and modification of porous solids, namely, zeolite structures and carbon materials from biomass through conventional and innovative approaches; characterization of materials through different techniques (e.g., physical adsorption of gases, adsorption of bases followed by infrared, X-ray diffraction, electron microscopies); study of the catalytic properties of zeolite materials in refining, petrochemistry, and fine chemistry such as Friedel–Crafts acylation reactions; application of carbon materials as adsorbents for the removal of pharmaceuticals from water (fundamental and applied studies); application of carbon materials for energy production and storage; carbon materials as catalysts or catalyst supports

Special Issue Information

Dear Colleagues,

Porous materials have attracted a large amount of interest due to their wide range of application in molecular separation, adsorption, and especially as catalysts or catalyst supports. A large set of porous materials such as zeolites and zeotypes, such as SAPOs, ALPOs, among others, metal organic frameworks (MOFs), carbon materials, and mesoporous silicas have in common the presence of a large surface area and pore volume. The micropores can act as microreactors, where the native active sites or introduced species, such as metals, promote the occurrence of catalytic reactions. On the other hand, the larger pores are ideal locations for the anchoring of bulky species such as enzymes or organometallic catalysts, preventing leaching and transforming homogeneous to environmentally friendly and reusable heterogeneous catalysts. 

The aim of this Special Issue is to open the discussion concerning the synthesis, modification, and functionalization of porous materials, aiming to prepare innovative and effective catalysts or catalyst supports for heterogeneous catalytic reactions.

Prof. Dr. Angela Martins
Prof. Dr. Ana Paula Carvalho
Guest Editors

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Keywords

  • Porous materials
  • Heterogeneous catalysts
  • Hierarchical materials
  • Bifunctional catalysts
  • Catalysts supports
  • Zeolites
  • Zeotypes
  • Carbon materials
  • MOFs
  • Mesoporous silicas

Published Papers (6 papers)

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Research

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Article
Influence of Surface Chemistry of Carbon Nanofibers on the Hydrodechlorination of Chloroform to Olefins
Catalysts 2022, 12(10), 1084; https://doi.org/10.3390/catal12101084 - 21 Sep 2022
Viewed by 303
Abstract
Functionalized carbon nanofibers (CNF) are fascinating materials to be used as supports in Pd-based catalysts for the treatment of waste chloroform (TCM) to produce light olefins through the catalytic hydrodechlorination (HDC). The CNF were functionalized by HNO3, HCl, and urea. Compared [...] Read more.
Functionalized carbon nanofibers (CNF) are fascinating materials to be used as supports in Pd-based catalysts for the treatment of waste chloroform (TCM) to produce light olefins through the catalytic hydrodechlorination (HDC). The CNF were functionalized by HNO3, HCl, and urea. Compared to the Pd supported on un-treated CNF, all the catalysts using functionalized CNF as support showed lower turnover frequency values with higher stability, owing to their smaller Pd nanoparticles (NPs). These smaller Pd NPs are formed due to the stronger metal–support interactions promoted by the higher concentration of surface groups on the functionalized catalysts. Since the smaller Pd NPs could hinder the hydrogenation of olefins to paraffins, the selectivity to olefins increased on the functionalized catalysts. Moreover, the N-doped CNF was successfully formed on the catalyst functionalized by urea. Since the nitrogen functional groups (pyridinic N and pyrrolic N) could provide much stronger metal–support interactions compared to the oxygen functional groups on the other catalysts, the catalyst functionalized by urea showed the smallest Pd NPs among the four catalysts, leading to the highest selectivity to light olefins. Full article
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Article
Exploring the Effect of Hierarchical Porosity in BEA Zeolite in Friedel-Crafts Acylation of Furan and Benzofuran
Catalysts 2022, 12(9), 1064; https://doi.org/10.3390/catal12091064 - 17 Sep 2022
Viewed by 307
Abstract
Hierarchical BEA zeolite was prepared through desilication or desilication followed by acid treatment. The catalytic performance of BEA zeolite samples was evaluated using Friedel-Crafts acylations with two substrates of different molecular sizes, furan (5.7 Å) and benzofuran (6.9 Å), in the presence of [...] Read more.
Hierarchical BEA zeolite was prepared through desilication or desilication followed by acid treatment. The catalytic performance of BEA zeolite samples was evaluated using Friedel-Crafts acylations with two substrates of different molecular sizes, furan (5.7 Å) and benzofuran (6.9 Å), in the presence of acetic anhydride as acylating agent. The application of the simplified Langmuir-Hinshelwood kinetic model showed that the size of the substrate leads to different catalytic activities, with improved rate constant and turnover frequency (TOF) solely in the presence of benzofuran for both desilicated and further acid treated samples. The mesopores developed during the zeolite treatments have an important role as transportation channels by reducing diffusion limitations. The application of Quantitative Structure–Property Relationships (QSPR) allowed the finding of the most relevant properties of the zeolite and substrate with impact on the catalytic parameters. Full article
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Article
Activity and Stability of Pd Bimetallic Catalysts for Catalytic Nitrate Reduction
Catalysts 2022, 12(7), 729; https://doi.org/10.3390/catal12070729 - 30 Jun 2022
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Abstract
In this work, we study the effect of modifying the metal loading (0.5–1.5 wt.% Pd and 0.1–1 wt.% Sn or In), the impregnation order of noble or promoter metal (Pd–Sn or Sn–Pd), and the type of promoter metal (Sn or In) during the [...] Read more.
In this work, we study the effect of modifying the metal loading (0.5–1.5 wt.% Pd and 0.1–1 wt.% Sn or In), the impregnation order of noble or promoter metal (Pd–Sn or Sn–Pd), and the type of promoter metal (Sn or In) during the preparation process for a Pd bimetallic catalyst, supported on γ-alumina, used in the catalytic reduction of nitrate. The deposition of the noble metal over the promoter metal, especially with Pd:Sn ratios (wt.) of 1:10 and 1:2, favored the hydrogen spillover rate and increased the H concentration on the catalyst surface, enhancing NH4+ production. On the other hand, Pd–In catalysts showed higher activity than the Sn catalysts, as well as higher NH4+ selectivity. The stability of the Pd–Sn/Al2O3 (1.5–1 wt.%) catalyst was evaluated in long-term experiments for the treatment of synthetic water (100 mg L−1 NO3) and three different commercial drinking waters. This Pd–Sn/Al2O3 catalyst achieved a stable nitrate conversion for a duration of 50 h in the synthetic water treatment. However, the catalyst showed a significant activity loss in the presence of other ions (different to NO3) in the reaction medium, increasing slightly the selectivity to NH4+. Full article
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Article
Fenton-Type Bimetallic Catalysts for Degradation of Dyes in Aqueous Solutions
Catalysts 2021, 11(1), 32; https://doi.org/10.3390/catal11010032 - 30 Dec 2020
Cited by 2 | Viewed by 931
Abstract
Dye compounds are becoming a problematic class of pollutants for the environment, so it is important to develop stable catalysts for their elimination. First, several studies were performed with different Y zeolites (NaY, (NH4)Y and USY) in order to select the [...] Read more.
Dye compounds are becoming a problematic class of pollutants for the environment, so it is important to develop stable catalysts for their elimination. First, several studies were performed with different Y zeolites (NaY, (NH4)Y and USY) in order to select the best support for the preparation of the bimetallic catalysts. In particular, NaY zeolite was used as the support for Fe, Cu and Mn metals to prepare mono and bimetallic Fenton-type catalysts by the ion exchange method. The catalysts were characterized by several techniques, such as chemical analysis, nitrogen physisorption, X-ray diffraction (XRD), scanning electron microscopy (SEM) and cyclic voltammetry studies. Characterization results revealed that the metals were successfully ion-exchanged within the NaY zeolite. The prepared catalysts were tested for the aqueous-phase degradation of dye compounds (Procion yellow (PY) and Tartrazine (Tar)) at atmospheric pressure and different temperatures, using H2O2 as the oxidant. All the investigated samples were found to be active in degrading the dyes through the Fenton-type process; however, the oxidation rate was found to be higher in the presence of the bimetallic catalysts. CuFe-NaY displays the best mineralization rate for PY oxidation while MnFe-NaY shows the highest activity for Tar degradation. This work may provide further insight into the design of Fenton-type bimetallic catalysts with improved catalytic properties for environmental remediation. Full article
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Article
Vapor-Phase Furfural Decarbonylation over a High-Performance Catalyst of 1%Pt/SBA-15
Catalysts 2020, 10(11), 1304; https://doi.org/10.3390/catal10111304 - 12 Nov 2020
Cited by 4 | Viewed by 780
Abstract
A high-performance Pt catalyst supported on SBA-15 was developed for furfural decarbonylation. Compared to Pt catalysts loaded on microporous DeAl-Hbeta zeolite and hierarchical micro-mesoporous MFI nanosheet (NS) materials, the 1%Pt/SBA-15 catalyst afforded notably higher activity, furan selectivity and stability owing to the negligible [...] Read more.
A high-performance Pt catalyst supported on SBA-15 was developed for furfural decarbonylation. Compared to Pt catalysts loaded on microporous DeAl-Hbeta zeolite and hierarchical micro-mesoporous MFI nanosheet (NS) materials, the 1%Pt/SBA-15 catalyst afforded notably higher activity, furan selectivity and stability owing to the negligible acid sites and proper mesopores on the SBA-15 support. Among a set of 1%Pt/SBA-15 catalysts bearing Pt nanoparticles (NPs) with sizes of 2.4–4.3 nm, the catalyst with 3.7 nm Pt NPs afforded the highest furan selectivity. Over the optimal catalyst, 88.6% furan selectivity and ca. 90% furfural conversion were obtained at 573 K and a high weight hourly space velocity (WHSV) of 16.5 h−1. Moreover, the reaction temperatures at 440–573 K and the ratios of H2 to furfural at 0.79–9.44 did not affect the reaction selectivity notably, showing that the reaction over 1%Pt/SBA-15 can be conducted over a wide range of conditions. The catalyst was stable under the harsh reaction conditions and lasted for 90 h without significant deactivation, demonstrating the superior property of SBA-15 as a catalyst support for furfural decarbonylation. Full article
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Review

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Review
Zeolites and Related Materials as Catalyst Supports for Hydrocarbon Oxidation Reactions
Catalysts 2022, 12(2), 154; https://doi.org/10.3390/catal12020154 - 26 Jan 2022
Cited by 2 | Viewed by 1069
Abstract
Catalytic oxidation is a key technology for the conversion of petroleum-based feedstocks into useful chemicals (e.g., adipic acid, caprolactam, glycols, acrylates, and vinyl acetate) since this chemical transformation is always involved in synthesis processes. Millions of tons of these compounds are annually produced [...] Read more.
Catalytic oxidation is a key technology for the conversion of petroleum-based feedstocks into useful chemicals (e.g., adipic acid, caprolactam, glycols, acrylates, and vinyl acetate) since this chemical transformation is always involved in synthesis processes. Millions of tons of these compounds are annually produced worldwide and find applications in all areas of chemical industries, ranging from pharmaceutical to large-scale commodities. The traditional industrial methods to produce large amounts of those compounds involve over-stoichiometric quantities of toxic inorganic reactants and homogeneous catalysts that operate at high temperature, originating large amounts of effluents, often leading to expensive downstream processes, along with nonrecovery of valuable catalysts that are loss within the reactant effluent. Due to the increasingly stringent environmental legislation nowadays, there is considerable pressure to replace these antiquate technologies, focusing on heterogeneous catalysts that can operate under mild reactions conditions, easily recovered, and reused. Parallelly, recent advances in the synthesis and characterization of metal complexes and metal clusters on support surfaces have brought new insights to catalysis and highlight ways to systematic catalysts design. This review aims to provide a comprehensive bibliographic examination over the last 10 years on the development of heterogeneous catalysts, i.e., organometallic complexes or metal clusters immobilized in distinct inorganic supports such as zeolites, hierarchical zeolites, silicas, and clays. The methodologies used to prepare and/or modify the supports are critically reviewed, as well as the methods used for the immobilization of the active species. The applications of the heterogenized catalysts are presented, and some case-studies are discussed in detail. Full article
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