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13 pages, 11627 KiB

Open AccessArticle

The Activity and Cyclic Catalysis of Synthesized Iron-Supported Zr/Ti Solid Acid Catalysts in Methyl Benzoate Compounds

by Chunjie Shi, Xiaofeng Yu, Wei Wang, Haibing Wu, Ai Zhang and Shengjin Liu

Catalysts 2023, 13(6), 971; https://doi.org/10.3390/catal13060971 - 2 Jun 2023

Cited by 1 | Viewed by 1701

Abstract

The catalytic activity and cyclic catalysis of different methyl benzoates were studied by using a series of Lewis solid acid catalysts. The iron-supported zirconium/titanium solid acid catalysts were characterized using FTIR, SEM, XRD, and BET. The details of catalytic activity and cyclic catalysis [...] Read more.

The catalytic activity and cyclic catalysis of different methyl benzoates were studied by using a series of Lewis solid acid catalysts. The iron-supported zirconium/titanium solid acid catalysts were characterized using FTIR, SEM, XRD, and BET. The details of catalytic activity and cyclic catalysis verified that the catalyst catalyzed the reactions of 31 benzoic acids with different substituents and methanol. In addition, the mechanism was revealed according to the microstructure, acid strength, and specific surface area of the catalysts, and the yields of methyl benzoates by the GC-MS. Zr ions had significant effects on the catalytic activity of the catalyst. A certain proportion of Fe and Ti ions additionally enhanced the catalytic activity of the catalyst, with the catalyst-specific composition of Fe:Zr:Ti = 2:1:1 showing optimal catalytic activity. A variety of substituents in the benzene ring, such as the electron-withdrawing group, the electron-donating group, large steric hindrance, and the position of the group on the benzene ring, had regular effects on the catalytic activity of the methyl benzoates. An increase in the catalyst activity occurred owing to the increases in the catalyst surface and the number of acid sites after the Fe ion was added. The catalytic activity remained unchanged after the facile recycling method was performed. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis for Fine Chemicals: Development of Sustainable Chemical Processes)

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18 pages, 3690 KiB

Open AccessArticle

Mechanochemical Synthesized CaO/ZnCo₂O₄ Nanocomposites for Biodiesel Production

by Katabathini Narasimharao, Mohamed Mokhtar M. Mostafa, Zahra M. Al-Amshany and Wejdan Bajafar

Catalysts 2023, 13(2), 398; https://doi.org/10.3390/catal13020398 - 13 Feb 2023

Cited by 9 | Viewed by 2217

Abstract

Biodiesel has been recognized as an environmentally friendly, renewable alternative to fossil fuels. In this work, CaO/ZnCo₂O₄ nanocomposites were successfully synthesized via simple mechanochemical reaction between ZnCo₂O₄ and CaO powders by varying the CaO loading from 5 [...] Read more.

Biodiesel has been recognized as an environmentally friendly, renewable alternative to fossil fuels. In this work, CaO/ZnCo₂O₄ nanocomposites were successfully synthesized via simple mechanochemical reaction between ZnCo₂O₄ and CaO powders by varying the CaO loading from 5 to 20 wt.%. The synthesized materials were found to be highly efficient heterogeneous catalysts for transesterification of tributyrin with methanol to produce biodiesel. The nanocomposite, which contained 20 wt.% CaO and 80 wt.% ZnCo₂O₄ (CaO/ZnCo₂O₄-20), exhibited superior and stable transesterification activity (98% conversion) under optimized reaction conditions (1:12 TBT to methanol molar ratio, 5 wt.% catalyst and 180 min. reaction time). The experimental results revealed that the reaction mechanism on the CaO/ZnCo₂O₄ composite followed pseudo first-order kinetics. The physicochemical characteristics of the synthesized nanocomposites were measured using X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), Fourier-transformed infrared spectroscopy (FTIR), X-ray photoelectron spectrometer (XPS), N₂-physisorption, and CO₂- temperature-programmed desorption (CO₂-TPD) techniques. The results indicated the existence of coalescence between the CaO and ZnCo₂O₄ particles, Additionally, the CaO/ZnCo₂O₄-20 catalyst was found to possess the greater number of highly basic sites and high porosity, which are the key factors affecting catalytic performance in transesterification reactions. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis for Fine Chemicals: Development of Sustainable Chemical Processes)

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13 pages, 9416 KiB

Open AccessArticle

Oxidation of Alcohols into Carbonyl Compounds Using a CuO@GO Nano Catalyst in Oxygen Atmospheres

by Maqsood Ahmad Malik, Ravikumar Surepally, Nagarjuna Akula, Ravi Kumar Cheedarala, Abdulmohsen Ali Alshehri and Khalid Ahmed Alzahrani

Catalysts 2023, 13(1), 55; https://doi.org/10.3390/catal13010055 - 27 Dec 2022

Cited by 3 | Viewed by 3012

Abstract

In this article, the oxidation of alcohols into carbonyl compounds was studied in oxygen atmospheres using a copper oxide on graphene oxide (CuO@GO) nano composites catalyst, synthesized by the wet chemistry method. CuO@GO nano composites were prepared from GO, and CuO NPs by [...] Read more.

In this article, the oxidation of alcohols into carbonyl compounds was studied in oxygen atmospheres using a copper oxide on graphene oxide (CuO@GO) nano composites catalyst, synthesized by the wet chemistry method. CuO@GO nano composites were prepared from GO, and CuO NPs by the sol-gel method. The transformation of aromatic alcohols into corresponding carbonyl compounds in good-to-high yields were observed using the CuO@GO catalyst under an oxygen atmosphere. Synthesized CuO@GO was confirmed by FT-IR, XRD, XPS, TEM, FE-SEM, TEM, and SEM analyses, and revealed intercalation of CuO-NPs on/in GO nano sheets through the chelation of Cu⁺² ions with CO, COOH, and OH groups presenting on the GO nano sheets. The catalytic activity of CuO@GO nano composites for the conversion of alcohols into carbonyl compounds were evaluated through TOF (2.56 × 10⁻³ mol g⁻¹ min⁻¹). The use of CuO@GO has shown catalytic activity and recyclability with a high conversion of alcohols to ketones. We assume that the proposed CuO@GO catalyst can be used for other key organic transformations and will be evaluated in the future. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis for Fine Chemicals: Development of Sustainable Chemical Processes)

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17 pages, 3764 KiB

Open AccessArticle

Green Hydrothermal Synthesis of Zinc Oxide Nanoparticles for UV-Light-Induced Photocatalytic Degradation of Ciprofloxacin Antibiotic in an Aqueous Environment

by Maha G. Batterjee, Arshid Nabi, Majid Rasool Kamli, Khalid Ahmed Alzahrani, Ekram Y. Danish and Maqsood Ahmad Malik

Catalysts 2022, 12(11), 1347; https://doi.org/10.3390/catal12111347 - 2 Nov 2022

Cited by 24 | Viewed by 4588

Abstract

The design and development of new cost-effective, clean, and efficient synthesis procedures for the synthesis of nanoparticles have recently become an intriguing research topic with broad implications. This study aimed to develop an eco-friendly biogenic method that uses minimum nontoxic chemicals to yield [...] Read more.

The design and development of new cost-effective, clean, and efficient synthesis procedures for the synthesis of nanoparticles have recently become an intriguing research topic with broad implications. This study aimed to develop an eco-friendly biogenic method that uses minimum nontoxic chemicals to yield ZnO nanoparticles with enhanced capabilities for degradation of pharmaceutical by-products. The present study used black dried lemon peel aqueous extract as a biological stabilizing agent to prepare pure and stable zinc oxide nanoparticles (LP-ZnO NPs). The surface morphology, elemental composition, crystalline properties, size, optical properties, the role of functional groups in stabilization, capping, and the thermal stability of LP-ZnO NPs were investigated using scanning electron microscopy equipped with energy dispersive X-ray (SEM-EDX), X-ray diffraction (XRD), UV–visible diffuse reflectance spectroscopy (UV-DRS), PL, Fourier transform infrared (FTIR), Raman spectra, and thermogravimetric (TGA) analyses. Multiphoton resonances were observed in LP-ZnO NPs along the crystalline structure as per Raman analysis. The developed LP-ZnO NPs were thermally stable at an annealing temperature of 500 °C with a weight loss of 53%. Photodegradation of antibiotic ciprofloxacin was observed in the presence of UV light via LP-ZnO NPs (serving as photocatalyst). In addition, in optimal reaction media, the biogenic LP-ZnO NPs retained improved photocatalytic performance toward ciprofloxacin. Meanwhile, in the photodegradation process of CPI molecules via ZnO as a photocatalyst, the optimum catalytic dose, concentration of CIP molecules, and pH were attained at 10 mg, 2 × 10⁻⁵ M, and pH 8, respectively. The aim of this research work was to develop a simple, affordable photocatalytic technique for the photodegradation of antibiotics in aqueous media. The photocatalytic process was performed under different experimental conditions, including varying catalytic doses, ciprofloxacin concentrations, and pH of the reaction mixture. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis for Fine Chemicals: Development of Sustainable Chemical Processes)

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17 pages, 5418 KiB

Open AccessArticle

Influence of Synthesis Conditions on Physicochemical and Photocatalytic Properties of Ag Containing Nanomaterials

by Salwa D. Al-Malwi, Rahmah H. Al-Ammari, Abdulmohsen Alshehri and Katabathini Narasimharao

Catalysts 2022, 12(10), 1226; https://doi.org/10.3390/catal12101226 - 13 Oct 2022

Cited by 3 | Viewed by 1568

Abstract

Silver (Ag) containing nanomaterials were successfully prepared by varying synthesis conditions to understand the influence of preparation conditions on the physicochemical and photocatalytic properties of these materials. Different analytical techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy [...] Read more.

Silver (Ag) containing nanomaterials were successfully prepared by varying synthesis conditions to understand the influence of preparation conditions on the physicochemical and photocatalytic properties of these materials. Different analytical techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Diffuse reflectance UV-vis spectra (DR UV-vis), X-ray photoelectron spectroscopy (XPS) measurements, and N₂-physisorption were used to investigate the physicochemical properties of synthesized Ag containing nanomaterials. The samples (Ag-1 and Ag-2) prepared using AgNO₃, NaHCO₃, and polyvinylpyrrolidone (PVP) template exhibited pure Ag metal nanorods and nanoparticles; the morphology of Ag metal is influenced by the hydrothermal treatment. The Ag-3 sample prepared without PVP template and calcined at 250 °C showed the presence of a pure Ag₂O phase. However, the same sample dried at 50 °C (Ag-4) showed the presence of a pure Ag₂CO₃ phase. Interestingly, subjecting the sample to hydrothermal treatment (Ag-5) has not resulted in any change in crystal structure, but particle size was increased. All the synthesized Ag containing nanomaterials were used as photocatalysts for p-nitrophenol (p-NP) degradation under visible light irradiation. The Ag-4 sample (pure Ag₂CO₃ with small crystallite size) exhibited high photocatalytic activity (86% efficiency at pH 10, p-NP concentration of 16 mg L⁻¹, 120 min and catalyst mass of 100 mg) compared to the other synthesized Ag containing nanomaterials. The high photocatalytic activity of the Ag-4 sample is possibly due to the presence of a pure Ag₂CO₃ crystal structure with nanorod morphology with a low band gap energy of 1.96 eV and relative high surface area. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis for Fine Chemicals: Development of Sustainable Chemical Processes)

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11 pages, 896 KiB

Open AccessArticle

Efficient and Eco-Friendly Perspectives for C-H Arylation of Benzothiazole Utilizing Pd Nanoparticle-Decorated Chitosan

by Mohamed Mokhtar M. Mostafa, Tamer S. Saleh, Salem M. Bawaked, Khadijah S. Alghamdi and Katabathini Narasimharao

Catalysts 2022, 12(9), 1000; https://doi.org/10.3390/catal12091000 - 5 Sep 2022

Cited by 6 | Viewed by 2349

Abstract

In this contribution, an eco-friendly, sustainable, and efficient palladium nanoparticle-decorated chitosan (Pd@Chitosan) catalyst was synthesized by a simple impregnation method. The synthesized material was utilized as a heterogeneous catalyst for the C-H arylation of benzothiazole under ultrasonic irradiation. The Pd@Chitosan catalyst efficiently catalyzed [...] Read more.

In this contribution, an eco-friendly, sustainable, and efficient palladium nanoparticle-decorated chitosan (Pd@Chitosan) catalyst was synthesized by a simple impregnation method. The synthesized material was utilized as a heterogeneous catalyst for the C-H arylation of benzothiazole under ultrasonic irradiation. The Pd@Chitosan catalyst efficiently catalyzed the conversion of aryl iodides and bromides to 1-(4-(benzothiazol-2-yl)phenyl)ethan-1-one selectively. A single product of 83–93% yield was obtained in N,N-dimethylformamide solvent at 80 °C for 2.5h. This study reveals that Pd@Chitosan is an efficient catalyst, which catalyzes the C-H arylation with good reaction yields. The activity of the Pd@Chitosan is due to the presence of highly dispersed Pd(0) nanoparticles on the surface of the chitosan and Pd²⁺; a tentative mechanism was proposed based on the XPS results of the fresh catalyst and spent catalyst. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis for Fine Chemicals: Development of Sustainable Chemical Processes)

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Review

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35 pages, 14056 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Recent Progress in Nickel and Silica Containing Catalysts for CO₂ Hydrogenation to CH₄

by Nadiyah Albeladi, Qana A. Alsulami and Katabathini Narasimharao

Catalysts 2023, 13(7), 1104; https://doi.org/10.3390/catal13071104 - 14 Jul 2023

Cited by 6 | Viewed by 2511

Abstract

The recent unusual weather changes occurring in different parts of the world are caused by global warming, a consequence of the release of extreme amounts of greenhouse gases into the atmosphere. Carbon dioxide (CO₂) is one of these greenhouse gasses, which [...] Read more.

The recent unusual weather changes occurring in different parts of the world are caused by global warming, a consequence of the release of extreme amounts of greenhouse gases into the atmosphere. Carbon dioxide (CO₂) is one of these greenhouse gasses, which can be captured and reused to generate fuel through the methanation process. Nickel- and silica-based catalysts have been recognized as promising catalysts due to their efficiency, availability, and low prices. However, these catalysts suffer from metal sintering at high temperatures. Researchers have achieved remarkable improvements through altering conventional synthesis methods, supports, metal loading amounts, and promoters. The modified routes have enhanced stability and activity while the supports offer large surface areas, dispersion, and strong metal–support interactions. Nickel loading affects the formed structure and catalytic activity, whereas doping causes CO₂ conversion at low temperatures and forms basic sites. This review aims to discuss the CO₂ methanation process over Ni- and SiO₂-based catalysts, in particular the silica-supported Ni metal in previously reported research works and point out directions for potential future work. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis for Fine Chemicals: Development of Sustainable Chemical Processes)

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28 pages, 3061 KiB

Open AccessReview

Application of Heterogeneous Catalytic Ozonation in Wastewater Treatment: An Overview

by Xingxing Li, Li Fu, Fei Chen, Shichao Zhao, Jiangwei Zhu and Chengliang Yin

Catalysts 2023, 13(2), 342; https://doi.org/10.3390/catal13020342 - 3 Feb 2023

Cited by 49 | Viewed by 6360

Abstract

Catalytic ozonation is a non-selective mineralization technology of organic matter in water by using active free radicals generated by ozone degradation. Catalytic ozonation technology can be divided into homogeneous catalytic reactions using metal ions as catalysts and heterogeneous catalytic reactions using solid catalysts. [...] Read more.

Catalytic ozonation is a non-selective mineralization technology of organic matter in water by using active free radicals generated by ozone degradation. Catalytic ozonation technology can be divided into homogeneous catalytic reactions using metal ions as catalysts and heterogeneous catalytic reactions using solid catalysts. Homogeneous catalytic ozonation technology has many problems, such as low mineralization rate, secondary pollution caused by the introduction of metal ions and low utilization efficiency of oxidants, which limit its practical application. Compared with homogeneous catalytic ozonation technology, heterogeneous catalytic ozonation technology has the advantages of easy recovery, lower cost of water treatment, higher activity and improved mineralization rate of organic matter. This overview classifies and describes catalysts for heterogeneous catalytic ozonation technology, including the different types of metal oxides, metal-free catalysts, and substrates used to immobilize catalysts. In addition, the heterogeneous catalytic ozonation process involved in the multiphase complex reaction process is discussed. The effects of different parameters on the performance of heterogeneous catalytic ozonation are also discussed. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis for Fine Chemicals: Development of Sustainable Chemical Processes)

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