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M.Asiri A, Raza A, Khuram Shahzad M, Fadhali MM, Bahadar Khan S, Ahmad Alamry K, Alfifi SY, Marwani HM. Insight into the activation of persulfate with ZrO2 modified S-doped g-C3N4 nanocomposite for degradation of tetracycline hydrochloride. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.114486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Salomone F, Bonura G, Frusteri F, Castellino M, Fontana M, Chiodoni AM, Russo N, Pirone R, Bensaid S. Physico-Chemical Modifications Affecting the Activity and Stability of Cu-Based Hybrid Catalysts during the Direct Hydrogenation of Carbon Dioxide into Dimethyl-Ether. MATERIALS (BASEL, SWITZERLAND) 2022; 15:7774. [PMID: 36363366 PMCID: PMC9657723 DOI: 10.3390/ma15217774] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
The direct hydrogenation of CO2 into dimethyl-ether (DME) has been studied in the presence of ferrierite-based CuZnZr hybrid catalysts. The samples were synthetized with three different techniques and two oxides/zeolite mass ratios. All the samples (calcined and spent) were properly characterized with different physico-chemical techniques for determining the textural and morphological nature of the catalytic surface. The experimental campaign was carried out in a fixed bed reactor at 2.5 MPa and stoichiometric H2/CO2 molar ratio, by varying both the reaction temperature (200-300 °C) and the spatial velocity (6.7-20.0 NL∙gcat-1∙h-1). Activity tests evidenced a superior activity of catalysts at a higher oxides/zeolite weight ratio, with a maximum DME yield as high as 4.5% (58.9 mgDME∙gcat-1∙h-1) exhibited by the sample prepared by gel-oxalate coprecipitation. At lower oxide/zeolite mass ratios, the catalysts prepared by impregnation and coprecipitation exhibited comparable DME productivity, whereas the physically mixed sample showed a high activity in CO2 hydrogenation but a low selectivity toward methanol and DME, ascribed to a minor synergy between the metal-oxide sites and the acid sites of the zeolite. Durability tests highlighted a progressive loss in activity with time on stream, mainly associated to the detrimental modifications under the adopted experimental conditions.
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Affiliation(s)
- Fabio Salomone
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - Giuseppe Bonura
- Consiglio Nazionale delle Ricerche-Istituto di Tecnologie Avanzate per l’Energia “Nicola Giordano” (CNR-ITAE), Via Santa Lucia Sopra Contesse 5, 98126 Messina, Italy
| | - Francesco Frusteri
- Consiglio Nazionale delle Ricerche-Istituto di Tecnologie Avanzate per l’Energia “Nicola Giordano” (CNR-ITAE), Via Santa Lucia Sopra Contesse 5, 98126 Messina, Italy
| | - Micaela Castellino
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - Marco Fontana
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
- Istituto Italiano di Tecnologia (IIT), Via Livorno 60, 10144 Turin, Italy
| | | | - Nunzio Russo
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - Raffaele Pirone
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - Samir Bensaid
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
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Control of monomeric Vo's versus Vo clusters in ZrO 2-x for solar-light H 2 production from H 2O at high-yield (millimoles gr -1 h -1). Sci Rep 2022; 12:15132. [PMID: 36071088 PMCID: PMC9452565 DOI: 10.1038/s41598-022-19382-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/29/2022] [Indexed: 11/08/2022] Open
Abstract
Pristine zirconia, ZrO2, possesses high premise as photocatalyst due to its conduction band energy edge. However, its high energy-gap is prohibitive for photoactivation by solar-light. Currently, it is unclear how solar-active zirconia can be designed to meet the requirements for high photocatalytic performance. Moreover, transferring this design to an industrial-scale process is a forward-looking route. Herein, we have developed a novel Flame Spray Pyrolysis process for generating solar-light active nano-ZrO2−x via engineering of lattice vacancies, Vo. Using solar photons, our optimal nano-ZrO2−x can achieve milestone H2-production yield, > 2400 μmolg−1 h−1 (closest thus, so far, to high photocatalytic water splitting performance benchmarks). Visible light can be also exploited by nano-ZrO2−x at a high yield via a two-photon process. Control of monomeric Vo versus clusters of Vo’s is the key parameter toward Highly-Performing-Photocatalytic ZrO2−x. Thus, the reusable and sustainable ZrO2−x catalyst achieves so far unattainable solar activated photocatalysis, under large scale production.
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He ZH, Wu BT, Xia Y, Yang SY, Wang ZY, Wang K, Wang W, Yang Y, Liu ZT. CO2 oxidative dehydrogenation of n-butane to butadiene over CrOx supported on CeZr solid solution. MOLECULAR CATALYSIS 2022. [DOI: 10.1016/j.mcat.2022.112262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Zheng B, Fan J, Chen B, Qin X, Wang J, Wang F, Deng R, Liu X. Rare-Earth Doping in Nanostructured Inorganic Materials. Chem Rev 2022; 122:5519-5603. [PMID: 34989556 DOI: 10.1021/acs.chemrev.1c00644] [Citation(s) in RCA: 135] [Impact Index Per Article: 67.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Impurity doping is a promising method to impart new properties to various materials. Due to their unique optical, magnetic, and electrical properties, rare-earth ions have been extensively explored as active dopants in inorganic crystal lattices since the 18th century. Rare-earth doping can alter the crystallographic phase, morphology, and size, leading to tunable optical responses of doped nanomaterials. Moreover, rare-earth doping can control the ultimate electronic and catalytic performance of doped nanomaterials in a tunable and scalable manner, enabling significant improvements in energy harvesting and conversion. A better understanding of the critical role of rare-earth doping is a prerequisite for the development of an extensive repertoire of functional nanomaterials for practical applications. In this review, we highlight recent advances in rare-earth doping in inorganic nanomaterials and the associated applications in many fields. This review covers the key criteria for rare-earth doping, including basic electronic structures, lattice environments, and doping strategies, as well as fundamental design principles that enhance the electrical, optical, catalytic, and magnetic properties of the material. We also discuss future research directions and challenges in controlling rare-earth doping for new applications.
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Affiliation(s)
- Bingzhu Zheng
- State Key Laboratory of Silicon Materials, Institute for Composites Science Innovation, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Jingyue Fan
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Bing Chen
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR 999077, China
| | - Xian Qin
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Juan Wang
- Institute of Environmental Health, MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Feng Wang
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR 999077, China
| | - Renren Deng
- State Key Laboratory of Silicon Materials, Institute for Composites Science Innovation, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Xiaogang Liu
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
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Cerium-, Europium- and Erbium-Modified ZnO and ZrO2 for Photocatalytic Water Treatment Applications: A Review. Catalysts 2021. [DOI: 10.3390/catal11121520] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In the last decades photocatalysis has become one of the most employed technologies for the implementation of the so-called Advanced Oxidation Processes (AOPs) for the removal of harmful pollutants from wastewaters. The materials identified as the best photocatalysts are transition metal oxides, in which the band structure allows charge carrier separation upon solar irradiation. The photoinduced charge carrier can thus cause oxidative and reductive redox reactions at the surface, inducing the formation of the radical species able to initiate the AOPs. Despite the great advantages of this process (non-toxic, cheap and environmentally clean), the main drawback lies in the fact that the most efficient semiconductors are only able to absorb UV irradiation, which accounts for only 5% of the total solar irradiation at the Earth’s surface and not enough to generate the required amount of electron-hole pairs. On the other hand, many efforts have been devoted to the sensitization of wide band gap transition metal oxides to visible light, which represents a higher percentage (almost 45%) in the solar electromagnetic spectrum. Among all the strategies to sensitize transition metal oxides to visible irradiation, doping with lanthanides has been less explored. In this regard, lanthanides offer a unique electronic configuration, consisting in 4f orbitals shielded by a 5s5p external shell. This occurrence, coupled with the different occupation of the localized 4f orbitals would provide an astounding opportunity to tune these materials’ properties. In this review we will focus in depth on the modification of two promising photocatalytic transition metal oxides, namely ZnO and ZrO2, with cerium, europium and erbium atoms. The aim of the work is to provide a comprehensive overview of the influence of lanthanides on the structural, optical and electronic properties of the modified materials, emphasizing the effect of the different 4f orbital occupation in the three considered doping atoms. Moreover, a large portion of the discussion will be devoted to the structural-properties relationships evidencing the improved light absorption working mechanism of each system and the resulting enhanced photocatalytic performance in the abatement of contaminants in aqueous environments.
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Piticescu RR, Slobozeanu AE, Valsan SN, Ciobota CF, Ghita AN, Motoc AM, Chiriac S, Prakasam M. Hydrothermal Synthesis of Nanocrystalline ZrO 2-8Y 2O 3-xLn 2O 3 Powders (Ln = La, Gd, Nd, Sm): Crystalline Structure, Thermal and Dielectric Properties. MATERIALS 2021; 14:ma14237432. [PMID: 34885586 PMCID: PMC8658870 DOI: 10.3390/ma14237432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/26/2021] [Accepted: 11/26/2021] [Indexed: 11/16/2022]
Abstract
Zirconium dioxide (ZrO2) is one of the ceramic materials with high potential in many areas of modern technologies. ZrO2 doped with 8 wt.% (~4.5 mol%) Y2O3 is a commercial powder used for obtaining stabilized zirconia materials (8 wt.% YSZ) with high temperature resistance and good ionic conductivity. During recent years it was reported the co-doping with multiple rare earth elements has a significant influence on the thermal, mechanical and ionic conductivity of zirconia, due complex grain size segregation and enhanced oxygen vacancies mobility. Different methods have been proposed to synthesize these materials. Here, we present the hydrothermal synthesis of 8 wt.% (~4.5 mol%) YSZ co-doped with 4, 6 and 8 wt.% La2O3, Nd2O3, Sm2O3 and Gd2O3 respectively. The crystalline phases formed during their thermal treatment in a large temperature range were analyzed by X-ray diffraction. The evolution of phase composition vs. thermal treatment temperatures shows as a major trend the formation at temperatures >1000 °C of a cubic solid solutions enriched in the rare earth oxide used for co-doping as major phase. The first results on the thermal conductivities and impedance measurements on sintered pellets obtained from powders co-doped with 8 wt.% Y and 6% Ln (Ln = La, Nd, Sm and Gd) and the corresponding activation energies are presented and discussed. The lowest thermal conductivity was obtained for La co-doped 8 wt.% YSZ while the lowest activation energy for ionic conduction for Gd co-doped 8 wt.% YSZ materials.
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Affiliation(s)
- Radu-Robert Piticescu
- National R&D Institute for Non-Ferrous and Rare Metals, INCDMNR-IMNR, 102 Biruintei Blvd., 077145 Pantelimon, Romania; (S.N.V.); (C.F.C.); (A.-N.G.); (A.M.M.); (S.C.)
- Correspondence: (R.-R.P.); (A.E.S.)
| | - Anca Elena Slobozeanu
- National R&D Institute for Non-Ferrous and Rare Metals, INCDMNR-IMNR, 102 Biruintei Blvd., 077145 Pantelimon, Romania; (S.N.V.); (C.F.C.); (A.-N.G.); (A.M.M.); (S.C.)
- Correspondence: (R.-R.P.); (A.E.S.)
| | - Sorina Nicoleta Valsan
- National R&D Institute for Non-Ferrous and Rare Metals, INCDMNR-IMNR, 102 Biruintei Blvd., 077145 Pantelimon, Romania; (S.N.V.); (C.F.C.); (A.-N.G.); (A.M.M.); (S.C.)
| | - Cristina Florentina Ciobota
- National R&D Institute for Non-Ferrous and Rare Metals, INCDMNR-IMNR, 102 Biruintei Blvd., 077145 Pantelimon, Romania; (S.N.V.); (C.F.C.); (A.-N.G.); (A.M.M.); (S.C.)
| | - Andreea-Nicoleta Ghita
- National R&D Institute for Non-Ferrous and Rare Metals, INCDMNR-IMNR, 102 Biruintei Blvd., 077145 Pantelimon, Romania; (S.N.V.); (C.F.C.); (A.-N.G.); (A.M.M.); (S.C.)
| | - Adrian Mihail Motoc
- National R&D Institute for Non-Ferrous and Rare Metals, INCDMNR-IMNR, 102 Biruintei Blvd., 077145 Pantelimon, Romania; (S.N.V.); (C.F.C.); (A.-N.G.); (A.M.M.); (S.C.)
| | - Stefania Chiriac
- National R&D Institute for Non-Ferrous and Rare Metals, INCDMNR-IMNR, 102 Biruintei Blvd., 077145 Pantelimon, Romania; (S.N.V.); (C.F.C.); (A.-N.G.); (A.M.M.); (S.C.)
| | - Mythili Prakasam
- CNRS, Université de Bordeaux, ICMCB, UMR 5026, 87 Avenue du Docteur Schweitzer, CEDEX, 33608 Pessac, France;
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Dalmis R, Birlik I, Ak Azem NF, Celik E. Structurally colored silica photonic crystal coatings modified by Ce or Eu rare-earth dopants. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Photocatalytic Reduction of Cr(VI) in the Presence of Humic Acid Using Immobilized Ce-ZrO 2 under Visible Light. NANOMATERIALS 2020; 10:nano10040779. [PMID: 32325680 PMCID: PMC7221772 DOI: 10.3390/nano10040779] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/10/2020] [Accepted: 04/16/2020] [Indexed: 12/23/2022]
Abstract
Cr(VI) has several industrial applications but it is one of the most dangerous pollutants because of its carcinogenicity and high toxicity. Thus, the removal of Cr(VI) by photocatalytic reduction was investigated. The catalyst applied, Ce–ZrO2, was immobilized, through a sol–gel process on a silicon carbide (SiC) support, to increase the efficiency and avoid using suspended nanoparticles. The influence of initial pH, humic acid (HA), and catalyst dosage was investigated for Cr(VI) containing solutions. Then, a real galvanizing industry effluent (Cr(VI) = 77 mg L-1mg.L−1, Zn = 1789 mg L−1) was treated. It was observed that Cr(VI) adsorption and photoreduction are greatly favored at low pH values. HA can decrease Cr(VI) adsorption but also acts as holes scavenger, reducing the electron–hole recombination, favoring then the photoreduction. With the immobilized Ce–ZrO2, more than 97% of Cr(VI) was removed from the diluted effluent. These results indicate the feasibility to treat Cr(VI) effluents even in the presence of other metals and natural organic matter. The developed material has great chemical and mechanical resistances and avoids the use of nanoparticles, dangerous for the environment and hard to recover. Moreover, solar light can be used to drive the process, which contributes to the development of more sustainable, cleaner, and cost-effective wastewater treatments.
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Abstract
A Gasoline Particulate Filter (GPF) can be an effective solution to abate the particulate matter produced in modern direct injection gasoline engines. The regeneration of this system is critical, since it occurs in oxygen deficiency, but it can be promoted by placing an appropriate catalyst on the filter walls. In this paper, a nanostructured equimolar ceria-praseodymia catalyst, obtained via hydrothermal synthesis, was characterized with complementary techniques (XRD, N2-physisorption, FESEM, XPS, Temperature Programmed Reduction, etc.) and its catalytic performances were investigated in low oxygen availability. Pr-doping significantly affected ceria structure and morphology, and the weakening of the cerium–oxygen bond associated to Pr insertion resulted in a high reducibility. The catalytic activity was explored considering different reactions, namely CO oxidation, ethylene and propylene total oxidation, and soot combustion. Thanks to its capability of releasing active oxygen species, ceria-praseodymia exhibited a remarkable activity and CO2-selectivity at low oxygen concentrations, proving to be a promising catalyst for coated GPFs.
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Control of Membrane Fouling in Organics Filtration Using Ce-Doped Zirconia and Visible Light. NANOMATERIALS 2019; 9:nano9040534. [PMID: 30987140 PMCID: PMC6523972 DOI: 10.3390/nano9040534] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 03/14/2019] [Accepted: 03/28/2019] [Indexed: 11/17/2022]
Abstract
Membrane fouling has been a major issue in the development of more efficient water treatment processes. Specifically in surface waters filtration, organic matter, such as humic-like substances, can cause irreversible fouling. Therefore, this study evaluates the activity of a photocatalytic layer composed of Ce-doped zirconia nanoparticles in improving the fouling resistance during filtration of an aqueous solution of humic acid (HA). These nanoparticles were prepared by hydrothermal and sol-gel processes and then characterized. Before the filtration experiments, the photodegradation of HA catalyzed by Ce-doped zirconia nanoparticles in dispersion was studied. It was observed that the sol-gel prepared Ce-ZrO₂ exhibited higher HA removal in practically neutral pH, achieving 93% efficiency in 180 min of adsorption in the dark followed by 180 min under visible-light irradiation using light-emitting diodes (LEDs). Changes in spectral properties and in total organic carbon confirmed HA degradation and contributed to the proposal of a mechanism for HA photodegradation. Finally, in HA filtration tests, Ce-ZrO₂ photocatalytic membranes were able to recover the flux in a fouled membrane using visible-light by degrading HA. The present findings point to the further development of anti-fouling membranes, in which solar light can be used to degrade fouling compounds and possibly contaminants of emerging concern, which will have important environmental implications.
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