Research

Jump to: Review

18 pages, 2712 KiB

Open AccessArticle

Synthesis of Co,Ce Oxide Nanoparticles Using an Aerosol Method and Their Deposition on Different Structured Substrates for Catalytic Removal of Diesel Particulate Matter

by María Laura Godoy, Ezequiel David Banús, Micaela Bon, Eduardo Ernesto Miró and Viviana Guadalupe Milt

Catalysts 2023, 13(4), 660; https://doi.org/10.3390/catal13040660 - 28 Mar 2023

Cited by 3 | Viewed by 1356

Abstract

The synthesis of Co and Ce oxide nanoparticles using precipitation of precursor salt solutions in the form of microdroplets generated with a nebulizer proved to be an efficient, fast and inexpensive method. Different morphologies of single oxides particles were obtained. Ceria nanoparticles were [...] Read more.

The synthesis of Co and Ce oxide nanoparticles using precipitation of precursor salt solutions in the form of microdroplets generated with a nebulizer proved to be an efficient, fast and inexpensive method. Different morphologies of single oxides particles were obtained. Ceria nanoparticles were almost cube-shaped of 8 nm average size, forming 1.3–1.5 μm aggregates, whereas cobalt oxide appeared as rounded-edged particles of 37 nm average size, mainly forming nanorods 50–500 nm. Co₃O₄ and CeO₂ nanoparticles were used to generate structured catalysts from both metallic (stainless steel wire mesh monoliths) and ceramic (cordierite honeycombs) substrates. Ceria Nyacol was used as a binder to favor the anchoring of catalytic particles thus enhancing the adhesion of the coating. The resulting structured catalysts were tested for the combustion of diesel soot with the aim of being used in the regeneration of particulate filters (DPFs). The performance of these structured catalysts was similar to or even better than that exhibited by the catalysts prepared using commercial nanoparticles. Among the catalysts tested, the structured systems using ceramic substrates were more efficient, showing lower values of the maximum combustion rate temperatures (T_M = 410 °C). Full article

(This article belongs to the Special Issue Nanoparticles in the Catalysis)

► Show Figures

Graphical abstract

16 pages, 32915 KiB

Open AccessArticle

The PtM/C (M = Co, Ni, Cu, Ru) Electrocatalysts: Their Synthesis, Structure, Activity in the Oxygen Reduction and Methanol Oxidation Reactions, and Durability

by Sergey Belenov, Angelina Pavlets, Kirill Paperzh, Dmitry Mauer, Vladislav Menshikov, Anastasia Alekseenko, Ilia Pankov, Mikhail Tolstunov and Vladimir Guterman

Catalysts 2023, 13(2), 243; https://doi.org/10.3390/catal13020243 - 20 Jan 2023

Cited by 4 | Viewed by 1899

Abstract

PtM/C (M = Co, Ni, Cu, Ru) catalysts were prepared by wet-synthesis methods. The composition and structure of the synthesized materials were estimated by TXRF, XRD, TEM, HAADF-STEM, EDX, and TGA/DSC methods. According to the CV and LSV methods, the PtCu/C material is [...] Read more.

PtM/C (M = Co, Ni, Cu, Ru) catalysts were prepared by wet-synthesis methods. The composition and structure of the synthesized materials were estimated by TXRF, XRD, TEM, HAADF-STEM, EDX, and TGA/DSC methods. According to the CV and LSV methods, the PtCu/C material is characterized by the highest activity in the ORR compared to the other materials studied. The PtRu/C catalysts also exhibit the highest activity in the MOR. Studying the durability of the obtained bimetallic catalysts using accelerated stress testing has allowed for the detection of the most promising materials, whose characteristics would be superior to those of the commercial Pt/C analog. This study has shown that wet-synthesis methods allow obtaining bimetallic catalysts characterized by higher activity and enhanced durability. This research also indicates that special attention should be given to the possibility of scaling these synthesis techniques, which makes the aforementioned catalysts promising for commercial applications. Full article

(This article belongs to the Special Issue Nanoparticles in the Catalysis)

► Show Figures

Graphical abstract

18 pages, 3231 KiB

Open AccessArticle

Xanthan Gum-Mediated Silver Nanoparticles for Ultrasensitive Electrochemical Detection of Hg²⁺ Ions from Water

by Sadia Shakeel, Farah Naz Talpur, Sirajuddin, Nadia Anwar, Muhammad Aamir Iqbal, Adnan Ibrahim, Hassan Imran Afridi, Ahsanullah Unar, Awais Khalid, Inas A. Ahmed, Wen-Cheng Lai and Muhammad Sohail Bashir

Catalysts 2023, 13(1), 208; https://doi.org/10.3390/catal13010208 - 16 Jan 2023

Cited by 5 | Viewed by 2449

Abstract

An environmentally safe, efficient, and economical microwave-assisted technique was selected for the production of silver nanoparticles (AgNPs). To prepare uniformly disseminated AgNPs, xanthan gum (XG) was utilized as both a reducing and capping agent. UV–Vis spectroscopy was used to characterize the formed XG-AgNPs, [...] Read more.

An environmentally safe, efficient, and economical microwave-assisted technique was selected for the production of silver nanoparticles (AgNPs). To prepare uniformly disseminated AgNPs, xanthan gum (XG) was utilized as both a reducing and capping agent. UV–Vis spectroscopy was used to characterize the formed XG-AgNPs, with the absorption band regulated at 414 nm under optimized parameters. Atomic force microscopy was used to reveal the size and shape of XG-AgNPs. The interactions between the XG capping agent and AgNPs observed using Fourier transform infrared spectroscopy. The XG-AgNPs were placed in between glassy carbon electrode and Nafion^® surfaces and then deployed as sensors for voltammetric evaluation of mercury ions (Hg²⁺) using square-wave voltammetry as an analytical mode. Required Nafion^® quantities, electrode behavior, electrolyte characteristics, pH, initial potentials, accumulation potentials, and accumulation durations were all comprehensively investigated. In addition, an electrochemical mechanism for the oxidation of Hg²⁺ was postulated. With an exceptional limit of detection of 0.18 ppb and an R² value of 0.981, the sensors’ measured linear response range was 0.0007–0.002 µM Hg²⁺. Hg²⁺ evaluations were ultimately unaffected by the presence of many coexisting metal ions (Cd²⁺, Pb²⁺, Cr₂O₄, Co²⁺,Cu²⁺, CuSO₄). Spiked water samples were tested using the described approach, with Hg²⁺ recoveries ranging from 97% to 100%. Full article

(This article belongs to the Special Issue Nanoparticles in the Catalysis)

► Show Figures

Figure 1

13 pages, 3829 KiB

Open AccessArticle

Visible-Light-Driven CO₂ Reduction into Methanol Utilizing Sol-Gel-Prepared CeO₂-Coupled Bi₂O₃ Nanocomposite Heterojunctions

by Mohamed Mokhtar Mohamed Mostafa, Ahmed Shawky, Sharif Fakhruz Zaman, Katabathini Narasimharao, Mohamed Abdel Salam, Abdulmohsen Ali Alshehri, Nezar H. Khdary, Sulaiman Al-Faifi and Abhishek Dutta Chowdhury

Catalysts 2022, 12(11), 1479; https://doi.org/10.3390/catal12111479 - 19 Nov 2022

Cited by 13 | Viewed by 1797

Abstract

Carbon dioxide (CO₂) photoreduction into renewable fuels over semiconductor photocatalysts has emerged as a green and sustainable alternative for energy production. Consequently, tremendous efforts are being performed to develop robust and sustainable photocatalysts. Therefore, visible-light active nanocomposite photocatalysts composed of 5.0–20.0 [...] Read more.

Carbon dioxide (CO₂) photoreduction into renewable fuels over semiconductor photocatalysts has emerged as a green and sustainable alternative for energy production. Consequently, tremendous efforts are being performed to develop robust and sustainable photocatalysts. Therefore, visible-light active nanocomposite photocatalysts composed of 5.0–20.0 wt.% bismuth oxide (Bi₂O₃) and cerium oxide (CeO₂) were synthesized by a sol-gel-based process. The prepared nanocomposites were evaluated for the promoted photocatalytic reduction of CO₂ into methanol (CH₃OH). Various characterizations of the obtained photocatalysts exposed an outstanding development of crystalline structure, morphology, and surface texture due to the presence of Bi₂O₃. Moreover, the absorbance of light in the visible regime was improved with enhanced charge separation, as revealed by the exploration of optical response, photoluminescence, and photocurrent measurements. The overall bandgap calculations revealed a reduction to 2.75 eV for 15% Bi₂O₃/CeO₂ compared to 2.93 eV for pure CeO₂. Moreover, the adjusted 2.8 g L⁻¹ dose of 15% Bi₂O₃/CeO₂ selectively produced 1300 μmol g⁻¹ CH₃OH after 9 h of visible light irradiation. This photocatalyst also exhibits bearable reusability five times. The improved progression of 15% Bi₂O₃/CeO₂ is denoted by significant charge separation as well as enhanced mobility. This study suggests the application of metal oxide-based heterojunctions for renewable fuel production under visible light. Full article

(This article belongs to the Special Issue Nanoparticles in the Catalysis)

► Show Figures

Graphical abstract

18 pages, 6652 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Highly Active Ag-Cu Nanocrystal Catalyst-Coated Brewer’s Spent Grain Biochar for the Mineralization of Methyl Orange and Methylene Blue Dye Mixture

by Lahcen Boubkr, Arvind K. Bhakta, Youssef Snoussi, Cora Moreira Da Silva, Laurent Michely, Mohamed Jouini, Souad Ammar and Mohamed M. Chehimi

Catalysts 2022, 12(11), 1475; https://doi.org/10.3390/catal12111475 - 18 Nov 2022

Cited by 7 | Viewed by 2355

Abstract

The aim of the present work is to valorise the brewing industry’s waste, i.e., brewer’s spent grain (BSG), into functional biocarbon for environmental catalysis applications. In this context, cost-effective and environmentally friendly biochar support coated with in-situ-generated Ag-Cu nanocrystals, was developed via the [...] Read more.

The aim of the present work is to valorise the brewing industry’s waste, i.e., brewer’s spent grain (BSG), into functional biocarbon for environmental catalysis applications. In this context, cost-effective and environmentally friendly biochar support coated with in-situ-generated Ag-Cu nanocrystals, was developed via the wet impregnation of BSG biomass powder with copper (II) nitrate trihydrate and silver nitrate aqueous solution prior to pyrolysis at moderate temperature (500 °C). Small-size homogenously distributed Ag-Cu nanocrystals (≤80 nm) on the surface of the biochar (Biochar@Ag-Cu) were observed by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Elemental compositions were determined by X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray analysis (EDX). The crystalline nature of the nanoparticles was confirmed by X-ray powder diffraction (XRD). Information about the thermal stability of the materials and quality were obtained by thermogravimetric analysis (TGA) and Raman, respectively. The potentiality of the Biochar@Ag-Cu catalyst in the field of pollutant removal is demonstrated by taking methyl orange and methylene blue as model dyes. A kinetics study was performed and analyzed by UV–vis spectroscopy. Its highly active catalytic nature is proved by the complete mineralization of the methyl orange dye (100%) through oxidative degradation. The reusability of the catalyst has shown 96% removal efficiency after 3 cycles. The linear plot of −Ln (C_A/C₀) vs. time (R² = 0.9892) reveals that the mineralization of the methyl orange dye follows pseudo-first-order kinetics (k = 0.603 × 10⁻² min⁻¹). A methyl orange + methylene blue dye mixture degradation study has revealed the faster kinetics of the present catalyst towards methylene blue degradation. The current study suggests that BSG Biochar@Ag-Cu can be a potential candidate in contribution towards SDG 6. Full article

(This article belongs to the Special Issue Nanoparticles in the Catalysis)

► Show Figures

Graphical abstract

16 pages, 3252 KiB

Open AccessEditor’s ChoiceArticle

Activity and Structure of Nano-Sized Cobalt-Containing Systems for the Conversion of Lignin and Fuel Oil to Synthesis Gas and Hydrocarbons in a Microwave-Assisted Plasma Catalytic Process

by Mark V. Tsodikov, Olga V. Bukhtenko, Alexander V. Naumkin, Sergey A. Nikolaev, Andrey V. Chistyakov and Grigory I. Konstantinov

Catalysts 2022, 12(11), 1315; https://doi.org/10.3390/catal12111315 - 27 Oct 2022

Viewed by 1272

Abstract

In this study, we present the results of lignin and fuel oil conversion to hydrogen, synthesis gas, and liquid hydrocarbons in the presence of nano-sized cobalt-containing systems in a microwave-assisted plasma catalytic process. The deposition of a small amount of cobalt on lignin [...] Read more.

In this study, we present the results of lignin and fuel oil conversion to hydrogen, synthesis gas, and liquid hydrocarbons in the presence of nano-sized cobalt-containing systems in a microwave-assisted plasma catalytic process. The deposition of a small amount of cobalt on lignin increases its microwave absorption capacity and provides plasma generation in the reaction zone. The role of Co-containing particles in the above catalytic reactions is probably to activate the carbon bonds of lignin, which substantially increases the microwave absorption capacity of the system as a whole. The subsequent use of the cobalt-containing residue of lignin conversion as a catalytic system and MWI-absorbing material results in active fuel oil pyrolysis in a plasma catalytic process to afford gaseous and liquid hydrocarbons. In the plasma catalytic pyrolysis, fuel oil conversion is probably accompanied by the conversion of the organic matter of the residue and agglomeration of cobalt oxide particles. Full article

(This article belongs to the Special Issue Nanoparticles in the Catalysis)

► Show Figures

Graphical abstract

15 pages, 3441 KiB

Open AccessFeature PaperArticle

Photoelectrocatalytic Properties of a Ti-Modified Nanocrystalline Hematite Film Photoanode

by Vitali A. Grinberg, Victor V. Emets, Natalia A. Mayorova, Aleksey A. Averin and Andrei A. Shiryaev

Catalysts 2022, 12(10), 1243; https://doi.org/10.3390/catal12101243 - 15 Oct 2022

Cited by 4 | Viewed by 1390

Abstract

Photoelectrocatalytic oxidation of methanol, ethylene glycol, glycerol, and 5,6,7,8-tetrahydro-2-naphthol on thin-film nanocrystalline hematite electrodes fabricated by electrochemical deposition and promoted with spin-coated titanium has been studied. It is shown that the modification of hematite transforms it into material exhibiting high activity in the [...] Read more.

Photoelectrocatalytic oxidation of methanol, ethylene glycol, glycerol, and 5,6,7,8-tetrahydro-2-naphthol on thin-film nanocrystalline hematite electrodes fabricated by electrochemical deposition and promoted with spin-coated titanium has been studied. It is shown that the modification of hematite transforms it into material exhibiting high activity in the photoelectrochemical process of substrate oxidation upon illumination with light in the visible region of the spectrum. The highest activity is observed in the reaction of photoelectrocatalytic oxidation of glycerol. Results of intensity-modulated photocurrent spectroscopy (IMPS) suggest that the effect is due to an increased rate of charge transfer in the process of photoelectro-oxidation and efficient suppression of the recombination of generated electron-hole pairs. Therefore, thin-film photoanodes based on modified hematite are promising for practical application in the photooxidation of glycerol, a by-product of biofuel production, as well as in the photoelectrochemical degradation of other organic pollutants, including those formed during the production of pharmaceuticals. Full article

(This article belongs to the Special Issue Nanoparticles in the Catalysis)

► Show Figures

Figure 1

16 pages, 8990 KiB

Open AccessArticle

Deposition of Pt Nanoparticles by Ascorbic Acid on Composite Electrospun Polyacrylonitrile-Based Carbon Nanofiber for HT-PEM Fuel Cell Cathodes

by Igor I. Ponomarev, Kirill M. Skupov, Olga M. Zhigalina, Dmitry N. Khmelenin, Ivan I. Ponomarev, Elizaveta S. Vtyurina, Evgeny N. Cherkovskiy, Victoria G. Basu and Alexander D. Modestov

Catalysts 2022, 12(8), 891; https://doi.org/10.3390/catal12080891 - 13 Aug 2022

Cited by 1 | Viewed by 1851

Abstract

The efficient use of renewable energy sources requires development of new electrocatalytic materials for electrochemical energy storage systems, particularly fuel cells. To increase durability of high temperature polymer electrolyte fuel cell (HT-PEMFC), Pt/carbon black based catalysts should be replaced by more durable ones, [...] Read more.

The efficient use of renewable energy sources requires development of new electrocatalytic materials for electrochemical energy storage systems, particularly fuel cells. To increase durability of high temperature polymer electrolyte fuel cell (HT-PEMFC), Pt/carbon black based catalysts should be replaced by more durable ones, for example Pt/carbon nanofibers (CNF). Here, we report for the first time the quantitative ascorbic acid assisted deposition of Pt onto electrospun polyacrylonitrile-based CNF composite materials. The effect of their subsequent post-treatment at various temperatures (250 and 500 °C) and media (vacuum or argon-hydrogen mixture) on the Pt/C catalyst morphology is investigated. All obtained samples are thoroughly studied by high resolution electron microscopy, and Pt electrochemically active specific surface area was evaluated by cyclic voltammetry. Full article

(This article belongs to the Special Issue Nanoparticles in the Catalysis)

► Show Figures

Graphical abstract

15 pages, 8009 KiB

Open AccessArticle

L-asparagine Assisted Synthesis of Pt/CeO₂ Nanospheres for Toluene Combustion

by Yu Hao, Shaohua Chen, Xueyin Zhang and Tiehong Chen

Catalysts 2022, 12(8), 887; https://doi.org/10.3390/catal12080887 - 12 Aug 2022

Cited by 3 | Viewed by 1387

Abstract

Pt₁/CeO₂ nanospheres (Pt/CeO₂-NS) were synthesized by the bath oiling method with L-asparagine as a necessary additive. Owing to the morphology control effect and coordination interaction of L-asparagine, CeO₂ nanospheres can retain their nanosphere structure and show stronger [...] Read more.

Pt₁/CeO₂ nanospheres (Pt/CeO₂-NS) were synthesized by the bath oiling method with L-asparagine as a necessary additive. Owing to the morphology control effect and coordination interaction of L-asparagine, CeO₂ nanospheres can retain their nanosphere structure and show stronger electronic metal-support interaction with highly dispersed Pt. Moreover, the toluene catalytic combustion performance of Pt/CeO₂-NS was investigated. The structure-performance relationship is analyzed according to the coordination state of Pt. The Pt/CeO₂-NS catalyst exhibited superior catalytic activity than the commercial CeO₂-supported Pt catalyst, which is attributed to its higher oxygen vacancy and Pt⁴⁺. Full article

(This article belongs to the Special Issue Nanoparticles in the Catalysis)

► Show Figures

Figure 1

Review

Jump to: Research

20 pages, 5207 KiB

Open AccessReview

Carbon Dioxide Methanation Enabled by Biochar-Nanocatalyst Composite Materials: A Mini-Review

by Mengqi Tang, Ahmed Gamal, Arvind K. Bhakta, Khouloud Jlassi, Aboubakr M. Abdullah and Mohamed M. Chehimi

Catalysts 2024, 14(2), 155; https://doi.org/10.3390/catal14020155 - 19 Feb 2024

Viewed by 1026

Abstract

Due to ever-increasing global warming, the scientific community is concerned with finding immediate solutions to reduce or utilize carbon dioxide (CO₂) and convert it in useful compounds. In this context, the reductive process of CO₂ methanation has been well-investigated and [...] Read more.

Due to ever-increasing global warming, the scientific community is concerned with finding immediate solutions to reduce or utilize carbon dioxide (CO₂) and convert it in useful compounds. In this context, the reductive process of CO₂ methanation has been well-investigated and found to be attractive due to its simplicity. However, it requires the development of highly active catalysts. In this mini-review, the focus is on biochar-immobilized nanocatalysts for CO₂ methanation. We summarize the recent literature on the topic, reporting strategies for designing biochar with immobilized nanocatalysts and their performance in CO₂ methanation. We review the thermochemical transformation of biomass into biochar and its decoration with CO₂ methanation catalysts. We also tackle direct methods of obtaining biochar nanocatalysts, in one pot, from nanocatalyst precursor-impregnated biomass. We review the effect of the initial biomass nature, as well as the conditions that permit tuning the performances of the composite catalysts. Finally, we discuss the CO₂ methanation performance and how it could be improved, keeping in mind low operation costs and sustainability. Full article

(This article belongs to the Special Issue Nanoparticles in the Catalysis)

► Show Figures

Graphical abstract

18 pages, 1507 KiB

Open AccessReview

Bio-Fabrication of Trimetallic Nanoparticles and Their Applications

by Arpita Roy, Srijal Kunwar, Utsav Bhusal, Saad Alghamdi, Mazen Almehmadi, Hayaa M. Alhuthali, Mamdouh Allahyani, Md. Jamal Hossain, Md. Abir Hasan, Md. Moklesur Rahman Sarker and Mohd Fahami Nur Azlina

Catalysts 2023, 13(2), 321; https://doi.org/10.3390/catal13020321 - 01 Feb 2023

Cited by 5 | Viewed by 3045

Abstract

Nanoparticles are materials whose size is less than 100 nm. Because of their distinctive physical and chemical characteristics, nanoparticles have drawn considerable interest in a variety of fields. Biosynthesis of nanoparticles is a green and environmentally friendly technology, which requires fewer chemical reagents, [...] Read more.

Nanoparticles are materials whose size is less than 100 nm. Because of their distinctive physical and chemical characteristics, nanoparticles have drawn considerable interest in a variety of fields. Biosynthesis of nanoparticles is a green and environmentally friendly technology, which requires fewer chemical reagents, precursors, and catalysts. There are various types of nanomaterials, out of which trimetallic nanoparticles are receiving considerable interest in recent years. Trimetallic nanoparticles possess unique catalytic, biomedical, antimicrobial, active food packaging, and sensing applications as compared to monometallic or bimetallic nanoparticles. Trimetallic nanoparticles are currently synthesized by various methods such as chemical reduction, microwave-assisted, thermal, precipitation, and so on. However, most of these chemical and physical methods are expensive and toxic to the environment. Biological synthesis is one of the promising methods, which includes the use of bacteria, plants, fungi, algae, waste biomass, etc., as reducing agents. Secondary metabolites present in the biological agents act as capping and reducing agents. Green trimetallic nanoparticles can be used for different applications such as anticancer, antibacterial, antifungal, catalytic activity, etc. This review provides an overview of the synthesis of trimetallic nanoparticles using biological agents, and their applications in different areas such as anticancer, antimicrobial activity, drug delivery, catalytic activity, etc. Finally, current challenges, future prospects, and conclusions are highlighted. Full article

(This article belongs to the Special Issue Nanoparticles in the Catalysis)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Nanoparticles in the Catalysis

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (11 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI