Special Issue "Sustainable Applications in Surface Chemistry and Catalysis"

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

Deadline for manuscript submissions: closed (31 January 2019).

Special Issue Editors

Guest Editor
Prof. Dr. Carmela Aprile Website E-Mail
Unit of Nanomaterials Chemistry (CNano), Department of Chemistry, University of Namur (UNAMUR), Rue de Bruxelles 61, 5000 Namur, Belgium
Interests: heterogeneous catalysis; CO2 conversion; photocatalysis porous structured solids; nanoparticles; organic–inorganic hybrids; Silsesquioxanes
Guest Editor
Prof. Dr. Francesco Giacalone Website E-Mail
Dipartimento Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Viale delle Scienze, Ed. 17, 90128 Palermo, Italy
Interests: heterogeneous catalysis; carbon nanoforms; organic–inorganic hybrids; organocatalysis; ionic liquids

Special Issue Information

Dear Colleagues,

Heterogeneous catalysis covers a broad range of applications, influencing our daily lives at different levels. The search for efficient and sustainable catalytic processes is a challenging field that is in a state of constant evolution. This Special Issue is oriented to the sustainable applications of heterogeneous catalysis, from the state-of-the-art to the most recent advancements with a special focus on the design of novel materials, including (meso)porous solids, metal and metal oxide nanoparticles, and organic–inorganic hybrids. Reactions and processes of academic and industrial interest will be considered. Original contributions addressing the synthesis and characterization of heterogeneous catalysts, or those devoted to the in-depth understanding of the relationship between surface properties and catalytic performances/reaction mechanism, in the form of full papers or communications, are all welcome. Mini-reviews presenting an overview on the state-of-the-art with projections on future perspectives and trends in this domain will be also considered.

Prof. Dr. Carmela Aprile
Prof. Dr. Francesco Giacalone
Guest Editors

Manuscript Submission Information

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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 1600 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

  • sustainable chemistry
  • heterogeneous catalysis
  • structured porous solids
  • organic-inorganic hybrids
  • metal and metal oxides

Published Papers (9 papers)

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Research

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Open AccessArticle
Synthesis and Evaluation of Copper-Supported Titanium Oxide Nanotubes as Electrocatalyst for the Electrochemical Reduction of Carbon Oxide to Organics
Catalysts 2019, 9(3), 298; https://doi.org/10.3390/catal9030298 - 25 Mar 2019
Abstract
Carbon dioxide (CO2) is considered as the prime reason for the global warming effect and one of the useful ways to transform it into an array of valuable products is through electrochemical reduction of CO2 (ERC). This process requires an [...] Read more.
Carbon dioxide (CO2) is considered as the prime reason for the global warming effect and one of the useful ways to transform it into an array of valuable products is through electrochemical reduction of CO2 (ERC). This process requires an efficient electrocatalyst with high faradaic efficiency at low overpotential and enhanced reaction rate. Herein, we report an innovative way of reducing CO2 using copper-metal supported on titanium oxide nanotubes (TNT) electrocatalysts. The TNT support material was synthesized using alkaline hydrothermal process with Degussa (P-25) as a starting material. Copper nanoparticles were anchored on the TNT by homogeneous deposition-precipitation method (HDP) with urea as precipitating agent. The prepared catalysts were tested in a home-made H-cell with 0.5 M NaHCO3 aqueous solution in order to examine their activity for ERC and the optimum copper loading. Continuous gas-phase ERC was carried out in a solid polymer electrolyte (SPE) reactor. The 10% Cu/TNT catalysts were employed in the gas diffusion layer (GDL) on the cathode side with Pt-Ru/C on the anode side. Faradaic efficiencies for the three major products namely methanol, methane, and CO were found to be 4%, 3%, and 10%, respectively at −2.5 V with an overall current density of 120 mA/cm2. The addition of TNT significantly increased the catalytic activity of electrocatalyst for ERC. It is mainly attributed to their better stability towards oxidation, increased CO2 adsorption capacity and stabilization of the reaction intermediate, layered titanates, and larger surface area (400 m2/g) as compared with other support materials. Considering the low cost of TNT, it is anticipated that TNT support electrocatalyst for ECR will gain popularity. Full article
(This article belongs to the Special Issue Sustainable Applications in Surface Chemistry and Catalysis)
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Open AccessArticle
Photocatalytic Activity of Nanostructured Titania Films Obtained by Electrochemical, Chemical, and Thermal Oxidation of Ti6Al4V Alloy—Comparative Analysis
Catalysts 2019, 9(3), 279; https://doi.org/10.3390/catal9030279 - 19 Mar 2019
Abstract
Three different Ti6Al4V surface oxidation methods have been applied to obtain three types of titania materials of different nanoarchitecture. Electrochemical oxidation of titanium alloy allowed for obtaining titania nanotubes (TNT), chemical oxidation led to obtain titania nanofibers (TNF), and thermal oxidation gave titania [...] Read more.
Three different Ti6Al4V surface oxidation methods have been applied to obtain three types of titania materials of different nanoarchitecture. Electrochemical oxidation of titanium alloy allowed for obtaining titania nanotubes (TNT), chemical oxidation led to obtain titania nanofibers (TNF), and thermal oxidation gave titania nanowires (TNW). My earlier investigations of these nanomaterials were focused mainly on the estimation of their bioactivity and potential application in modern implantology. In this article, the comparative analysis of the photocatalytic activity of produced systems, as well as the impact of their structure and morphology on this activity, are discussed. The activity of studied nanomaterials was estimated basis of UV-induced degradation of methylene blue and also acetone, and it was determined quantitatively according to the Langmuir–Hinshelwood reaction mechanism. The obtained results were compared to the activity of Pilkington Glass ActivTM (reference sample). Among analyzed systems, titania nanofibers obtained at 140 and 120 °C, possessing anatase and anatase/amorphous structure, as well as titania nanowires obtained at 475 and 500 °C, possessing anatase and anatase/rutile structure, were better photocatalyst than the reference sample. Completely amorphous titania nanotubes, turned out to be an interesting alternative for photocatalytic materials in the form of thin films, however, their photocatalytic activity is lower than for Pilkington Glass ActivTM. Full article
(This article belongs to the Special Issue Sustainable Applications in Surface Chemistry and Catalysis)
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Open AccessArticle
Catalytic Behaviour of Flame-Made CuO-CeO2 Nanocatalysts in Efficient CO Oxidation
Catalysts 2019, 9(3), 256; https://doi.org/10.3390/catal9030256 - 13 Mar 2019
Cited by 1
Abstract
CuO-CeO2 nanocatalysts with varying CuO contents (1, 5, 9, 14 and 17 wt %) were prepared by one-step flame spray pyrolysis (FSP) and applied to CO oxidation. The influences of CuO content on the as-prepared catalysts were systematically characterized by X-ray diffraction [...] Read more.
CuO-CeO2 nanocatalysts with varying CuO contents (1, 5, 9, 14 and 17 wt %) were prepared by one-step flame spray pyrolysis (FSP) and applied to CO oxidation. The influences of CuO content on the as-prepared catalysts were systematically characterized by X-ray diffraction (XRD), N2 adsorption-desorption at −196 °C, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and hydrogen-temperature programmed reduction (H2-TPR). A superior CO oxidation activity was observed for the 14 wt % CuO-CeO2 catalyst, with 90% CO conversion at 98 °C at space velocity (60,000 mL × g−1 × h−1), which was attributed to abundant surface defects (lattice distortion, Ce3+, and oxygen vacancies) and high reducibility supported by strong synergistic interaction. In addition, the catalyst also displayed excellent stability and resistance to water vapor. Significantly, in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) showed that in the CO catalytic oxidation process, the strong synergistic interaction led readily to dehydroxylation and CO adsorption on Cu+ at low temperature. Furthermore, in the feed of water vapor, although there was an adverse effect on the access of CO adsorption, there was also a positive effect on the formation of fewer carbon intermediates. All these results showed the potential of highly active and water vapor-resistive CuO-CeO2 catalysts prepared by FSP. Full article
(This article belongs to the Special Issue Sustainable Applications in Surface Chemistry and Catalysis)
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Open AccessArticle
Appraisal of Sulphonation Processes to Synthesize Palm Waste Biochar Catalysts for the Esterification of Palm Fatty Acid Distillate
Catalysts 2019, 9(2), 184; https://doi.org/10.3390/catal9020184 - 15 Feb 2019
Cited by 2
Abstract
Palm waste biochar (PWB) catalysts were synthesized as bio-based catalysts using different sulphonation methods. (NH4)2SO4, ClSO3H, and H2SO4 were applied to functionalize PWB and appraise the discrepancies between the sulfonic agents, as [...] Read more.
Palm waste biochar (PWB) catalysts were synthesized as bio-based catalysts using different sulphonation methods. (NH4)2SO4, ClSO3H, and H2SO4 were applied to functionalize PWB and appraise the discrepancies between the sulfonic agents, as they affect the esterification reaction in terms of fatty acid methyl ester (FAME) yield and conversion while using palm fatty acid distillate (PFAD) as feedstock. The PWB was first soaked in phosphoric acid (H3PO4) for 24 h and then pyrolized at 400 °C for 2 h in tube furnace. Afterwards, sulphonation was done with different sulfonic agents and characterized with thermo-gravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), and temperature programmed desorption–ammonia (TPD-NH3). The three synthesized catalysts showed high free fatty acid (FFA) conversions of 90.1% for palm waste biochar-ammonium sulfate (PWB-(NH4)2SO4), 91.5% for palm waste biochar-chlorosulfonic acid (PWB-ClSO3H), and 97.4% for palm waste biochar - sulphuric acid (PWB-H2SO4), whereas FAME yields were 88.6% (PWB-(NH4)2SO4), 89.1% (PWB-ClSO3H), and 96.1% (PWB-H2SO4). It was observed that PWB-H2SO4 has the best catalytic activity, which was directly linked to its high acid density (11.35 mmol/g), improved pore diameter (6.25 nm), and increased specific surface area (372.01 m2 g−1). PWB-H2SO4 was used for the reusability study, where it underwent eight reaction runs and was stable until the seventh run. PWB-H2SO4 has shown huge promise for biodiesel synthesis, owing to its easy synthetic process, recyclability, and high catalytic activity for waste oils and fats. Full article
(This article belongs to the Special Issue Sustainable Applications in Surface Chemistry and Catalysis)
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Open AccessArticle
Ti-Doped Pd-Au Catalysts for One-Pot Hydrogenation and Ring Opening of Furfural
Catalysts 2018, 8(6), 252; https://doi.org/10.3390/catal8060252 - 20 Jun 2018
Cited by 3
Abstract
Pd-Au bimetallic catalysts with different Pd/Au atomic ratios, supported on ordered structured silica (Hexagonal mesoporous silica—HMS, or Santa Barbara Amorphous-15—SBA-15) were evaluated for one-pot hydrogenation of furfural to 1,2-pentanediol. The surface and structural properties of the catalysts were deeply investigated by X-ray photoelectron [...] Read more.
Pd-Au bimetallic catalysts with different Pd/Au atomic ratios, supported on ordered structured silica (Hexagonal mesoporous silica—HMS, or Santa Barbara Amorphous-15—SBA-15) were evaluated for one-pot hydrogenation of furfural to 1,2-pentanediol. The surface and structural properties of the catalysts were deeply investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), N2 adsorption isotherms (BET), Infrared spectroscopy (IR), and acid capacity measurements. XPS studies revealed that Ti doped supports had higher dispersion of the active phase, particularly in the case of Pd-Au materials in which Ti played an important role in stabilizing the metallic species. Among the various process conditions studied, such as temperature (160 °C), catalyst amount (10% w/w), and reaction time (5 h), H2 pressure (500 psi) was found to improve the 1,2-pentanediol selectivity. The SBA silica bimetallic Ti-doped system showed the best performance in terms of stability and reusability, after multiple cycles. Under specific reaction conditions, the synergism between Pd-Au alloy and Ti doping of the support allowed the ring opening pathway towards the formation of 1,2-pentanediol in furfural hydrogenation. Full article
(This article belongs to the Special Issue Sustainable Applications in Surface Chemistry and Catalysis)
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Review

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Open AccessReview
Mechanistic Insights into Photodegradation of Organic Dyes Using Heterostructure Photocatalysts
Catalysts 2019, 9(5), 430; https://doi.org/10.3390/catal9050430 - 09 May 2019
Cited by 7
Abstract
Due to its low cost, environmentally friendly process, and lack of secondary contamination, the photodegradation of dyes is regarded as a promising technology for industrial wastewater treatment. This technology demonstrates the light-enhanced generation of charge carriers and reactive radicals that non-selectively degrade various [...] Read more.
Due to its low cost, environmentally friendly process, and lack of secondary contamination, the photodegradation of dyes is regarded as a promising technology for industrial wastewater treatment. This technology demonstrates the light-enhanced generation of charge carriers and reactive radicals that non-selectively degrade various organic dyes into water, CO2, and other organic compounds via direct photodegradation or a sensitization-mediated degradation process. The overall efficiency of the photocatalysis system is closely dependent upon operational parameters that govern the adsorption and photodegradation of dye molecules, including the initial dye concentration, pH of the solution, temperature of the reaction medium, and light intensity. Additionally, the charge-carrier properties of the photocatalyst strongly affect the generation of reactive species in the heterogeneous photodegradation and thereby dictate the photodegradation efficiency. Herein, this comprehensive review discusses the pseudo kinetics and mechanisms of the photodegradation reactions. The operational factors affecting the photodegradation of either cationic or anionic dye molecules, as well as the charge-carrier properties of the photocatalyst, are also fully explored. By further analyzing past works to clarify key active species for photodegradation reactions and optimal conditions, this review provides helpful guidelines that can be applied to foster the development of efficient photodegradation systems. Full article
(This article belongs to the Special Issue Sustainable Applications in Surface Chemistry and Catalysis)
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Open AccessReview
Hybrid Catalysts for CO2 Conversion into Cyclic Carbonates
Catalysts 2019, 9(4), 325; https://doi.org/10.3390/catal9040325 - 02 Apr 2019
Cited by 3
Abstract
The conversion of carbon dioxide into valuable chemicals such as cyclic carbonates is an appealing topic for the scientific community due to the possibility of valorizing waste into an inexpensive, available, nontoxic, and renewable carbon feedstock. In this regard, last-generation heterogeneous catalysts are [...] Read more.
The conversion of carbon dioxide into valuable chemicals such as cyclic carbonates is an appealing topic for the scientific community due to the possibility of valorizing waste into an inexpensive, available, nontoxic, and renewable carbon feedstock. In this regard, last-generation heterogeneous catalysts are of great interest owing to their high catalytic activity, robustness, and easy recovery and recycling. In the present review, recent advances on CO2 cycloaddition to epoxide mediated by hybrid catalysts through organometallic or organo-catalytic species supported onto silica-, nanocarbon-, and metal–organic framework (MOF)-based heterogeneous materials, are highlighted and discussed. Full article
(This article belongs to the Special Issue Sustainable Applications in Surface Chemistry and Catalysis)
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Open AccessReview
Highlights of Major Progress on Single-Atom Catalysis in 2017
Catalysts 2019, 9(2), 135; https://doi.org/10.3390/catal9020135 - 01 Feb 2019
Abstract
Single-atom catalysis has rapidly progressed during the last few years. In 2017, single-atom catalysts (SACs) were fabricated with higher metal loadings and designed into more delicate structures. SACs also found wide applications in C1 chemical conversion, such as selective oxidation of methane and [...] Read more.
Single-atom catalysis has rapidly progressed during the last few years. In 2017, single-atom catalysts (SACs) were fabricated with higher metal loadings and designed into more delicate structures. SACs also found wide applications in C1 chemical conversion, such as selective oxidation of methane and conversion of carbon dioxide. Both experimental characterizations and computational modeling revealed the presence of tunable interactions between single atom species and their surrounding chemical environment, and thus SACs may be more effective and more stable than their nanoparticle counterparts. In this mini-review, we summarize the major achievements of SACs into three main aspects: (a) the advanced synthetic methodologies, (b) catalytic performance in C1 chemistry, and (c) strong metal-support interaction induced unexpected durability. These accomplishments will shed new light on the recognition of single-atom catalysis and encourage more efforts to explore potential applications of SACs. Full article
(This article belongs to the Special Issue Sustainable Applications in Surface Chemistry and Catalysis)
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Open AccessReview
The Mechanism of Adsorption, Diffusion, and Photocatalytic Reaction of Organic Molecules on TiO2 Revealed by Means of On-Site Scanning Tunneling Microscopy Observations
Catalysts 2018, 8(12), 616; https://doi.org/10.3390/catal8120616 - 04 Dec 2018
Abstract
The interaction of organic molecules and titanium dioxide (TiO2) plays a crucial role in many industry-oriented applications and an understanding of its mechanism can be helpful for the improvement of catalytic efficiency of TiO2. Scanning tunneling microscopy (STM) has [...] Read more.
The interaction of organic molecules and titanium dioxide (TiO2) plays a crucial role in many industry-oriented applications and an understanding of its mechanism can be helpful for the improvement of catalytic efficiency of TiO2. Scanning tunneling microscopy (STM) has been proved to be a powerful tool in characterizing reaction pathways due to its ability in providing on-site images during the catalytic process. Over the past two decades, many research interests have been focused on the elementary reaction steps, such as adsorption, diffusion, and photocatalytic reaction, occurring between organic molecules and model TiO2 surfaces. This review collects the recent studies where STM was utilized to study the interaction of TiO2 with three classes of representative organic molecules, i.e., alcohols, carboxylic acids, and aromatic compounds. STM can provide direct evidence for the adsorption configuration, diffusion route, and photocatalytic pathway. In addition, the combination of STM with other techniques, including photoemission spectroscopy (PES), temperature programmed desorption (TPD), and density functional theory (DFT), have been discussed for more insights related to organic molecules-TiO2 interaction. Full article
(This article belongs to the Special Issue Sustainable Applications in Surface Chemistry and Catalysis)
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