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Elmutasim O, Hussien AG, Sharan A, AlKhoori S, Vasiliades MA, Taha IMA, Kim S, Harfouche M, Emwas AH, Anjum DH, Efstathiou AM, Yavuz CT, Singh N, Polychronopoulou K. Evolution of Oxygen Vacancy Sites in Ceria-Based High-Entropy Oxides and Their Role in N 2 Activation. ACS APPLIED MATERIALS & INTERFACES 2024; 16. [PMID: 38684003 PMCID: PMC11082846 DOI: 10.1021/acsami.3c16521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 04/01/2024] [Accepted: 04/05/2024] [Indexed: 05/02/2024]
Abstract
In this work, a relatively new class of materials, rare earth (RE) based high entropy oxides (HEO) are discussed in terms of the evolution of the oxygen vacant sites (Ov) content in their structure as the composition changes from binary to HEO using both experimental and computational tools; the composition of HEO under focus is the CeLaPrSmGdO due to the importance of ceria-related (fluorite) materials to catalysis. To unveil key features of quinary HEO structure, ceria-based binary CePrO and CeLaO compositions as well as SiO2, the latter as representative nonreducible oxide, were used and compared as supports for Ru (6 wt % loading). The role of the Ov in the HEO is highlighted for the ammonia production with particular emphasis on the N2 dissociation step (N2(ads) → Nads) over a HEO; the latter step is considered the rate controlling one in the ammonia production. Density functional theory (DFT) calculations and 18O2 transient isotopic experiments were used to probe the energy of formation, the population, and the easiness of formation for the Ov at 650 and 800 °C, whereas Synchrotron EXAFS, Raman, EPR, and XPS probed the Ce-O chemical environment at different length scales. In particular, it was found that the particular HEO composition eases the Ov formation in bulk, in medium (Raman), and in short (localized) order (EPR); more Ov population was found on the surface of the HEO compared to the binary reference oxide (CePrO). Additionally, HEO gives rise to smaller and less sharp faceted Ru particles, yet in stronger interaction with the HEO support and abundance of Ru-O-Ce entities (Raman and XPS). Ammonia production reaction at 400 °C and in the 10-50 bar range was performed over Ru/HEO, Ru/CePrO, Ru/CeLaO, and Ru/SiO2 catalysts; the Ru/HEO had superior performance at 10 bar compared to the rest of catalysts. The best performing Ru/HEO catalyst was activated under different temperatures (650 vs 800 °C) so to adjust the Ov population with the lower temperature maintaining better performance for the catalyst. DFT calculations showed that the HEO active site for N adsorption involves the Ov site adjacent to the adsorption event.
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Affiliation(s)
- Omer Elmutasim
- Mechanical
Engineering Department, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
- Center
for Catalysis and Separation (CeCaS), Khalifa
University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Aseel G. Hussien
- Mechanical
Engineering Department, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
- Center
for Catalysis and Separation (CeCaS), Khalifa
University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Abhishek Sharan
- Center
for Catalysis and Separation (CeCaS), Khalifa
University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
- Physics
Department, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Sara AlKhoori
- Mechanical
Engineering Department, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
- Center
for Catalysis and Separation (CeCaS), Khalifa
University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Michalis A. Vasiliades
- Department
of Chemistry, Heterogeneous Catalysis Laboratory, University of Cyprus, 1 University Avenue, University Campus, 2109 Nicosia, Cyprus
| | | | - Seokjin Kim
- Oxide
& Organic Nanomaterials for Energy & Environment (ONE) Laboratory,
Advanced Membranes & Porous Materials (AMPM) Center, and KAUST
Catalysis Center (KCC), Physical Science & Engineering (PSE), King Abdullah University of Science and Technology
(KAUST), Thuwal 23955, Saudi Arabia
| | - Messaoud Harfouche
- Synchrotron-Light
for Experimental Science and Applications in the Middle East (SESAME), Allan 19252, Jordan
| | - Abdul-Hamid Emwas
- Core
Laboratories, King Abdullah University of
Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Dalaver H. Anjum
- Center
for Catalysis and Separation (CeCaS), Khalifa
University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
- Physics
Department, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Angelos M. Efstathiou
- Department
of Chemistry, Heterogeneous Catalysis Laboratory, University of Cyprus, 1 University Avenue, University Campus, 2109 Nicosia, Cyprus
| | - Cafer T. Yavuz
- Oxide
& Organic Nanomaterials for Energy & Environment (ONE) Laboratory,
Advanced Membranes & Porous Materials (AMPM) Center, and KAUST
Catalysis Center (KCC), Physical Science & Engineering (PSE), King Abdullah University of Science and Technology
(KAUST), Thuwal 23955, Saudi Arabia
| | - Nirpendra Singh
- Center
for Catalysis and Separation (CeCaS), Khalifa
University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
- Physics
Department, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Kyriaki Polychronopoulou
- Mechanical
Engineering Department, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
- Center
for Catalysis and Separation (CeCaS), Khalifa
University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
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Luo X, Xu L, Yang L, Zhao J, Asefa T, Qiu R, Huang Z. Ball Milling of La 2O 3 Tailors the Crystal Structure, Reactive Oxygen Species, and Free Radical and Non-Free Radical Photocatalytic Pathways. ACS APPLIED MATERIALS & INTERFACES 2024; 16:18671-18685. [PMID: 38591358 DOI: 10.1021/acsami.3c15677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
Non-free radical photocatalysis with metal oxide catalysts is an important advanced oxidation process that enables the removal of various emerging environmental pollutants, such as tetracycline. Here, four hexagonal La2O3 photocatalysts with different densities of oxygen vacancy and crystalline features are synthesized and then further treated by ball milling. Ball milling of these La2O3 photocatalysts is found to increase the amount of oxygen vacancies on their surfaces and thereby the amount of 1O2 species produced by them. The photocatalytic degradation of TC by these La2O3 photocatalysts depends on the oxygen vacancies present on them. Furthermore, the ones with a strong (101) diffraction peak remove tetracycline from water systems largely with 1O2 and •OH species, whereas those with a weak (101) diffraction peak do so mainly via 1O2 and direct electron transfer (DET) process. Their overall catalytic properties are also studied by density functional theory calculations. Moreover, the organic products produced from tetracycline by La2O3 photocatalysts containing a strong (101) diffraction peak are found to be less toxic than those produced by La2O3 photocatalysts containing a weak (101) diffraction peak. This study also provides convincing evidence that the structures of La2O3 determine the species that is produced by it and that end up mediating photocatalytic reaction pathways (i.e., free radical versus non-free radical) to degrade an emerging environment pollutant.
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Affiliation(s)
- Xuewen Luo
- Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Maoming Branch, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
| | - Lei Xu
- Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Maoming Branch, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
| | - Leba Yang
- Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Maoming Branch, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
| | - Jiawen Zhao
- Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Maoming Branch, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
| | - Tewodros Asefa
- Department of Chemistry and Chemical Biology & Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey 08854, United States
| | - Rongliang Qiu
- Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Maoming Branch, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
| | - Zhujian Huang
- Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Maoming Branch, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Street, Guangzhou 510642, China
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Tsiotsias A, Georgiadis AG, Charisiou ND, Hussien AGS, Dabbawala AA, Polychronopoulou K, Goula MA. Mid-temperature CO 2 Adsorption over Different Alkaline Sorbents Dispersed over Mesoporous Al 2O 3. ACS OMEGA 2024; 9:11305-11320. [PMID: 38496972 PMCID: PMC10938334 DOI: 10.1021/acsomega.3c07204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/19/2023] [Accepted: 12/28/2023] [Indexed: 03/19/2024]
Abstract
CO2 adsorbents comprising various alkaline sorption active phases supported on mesoporous Al2O3 were prepared. The materials were tested regarding their CO2 adsorption behavior in the mid-temperature range, i.e., around 300 °C, as well as characterized via XRD, N2 physisorption, CO2-TPD and TEM. It was found that the Na2O sorption active phase supported on Al2O3 (originated following NaNO3 impregnation) led to the highest CO2 adsorption capacity due to the presence of CO2-philic interfacial Al-O--Na+ sites, and the optimum active phase load was shown to be 12 wt % (0.22 Na/Al molar ratio). Additional adsorbents were prepared by dispersing Na2O over different metal oxide supports (ZrO2, TiO2, CeO2 and SiO2), showing an inferior performance than that of Na2O/Al2O3. The kinetics and thermodynamics of CO2 adsorption were also investigated at various temperatures, showing that CO2 adsorption over the best-performing Na2O/Al2O3 material is exothermic and follows the Avrami model, while tests under varying CO2 partial pressures revealed that the Langmuir isotherm best fits the adsorption data. Lastly, Na2O/Al2O3 was tested under multiple CO2 adsorption-desorption cycles at 300 and 500 °C, respectively. The material was found to maintain its CO2 adsorption capacity with no detrimental effects on its nanostructure, porosity and surface basic sites, thereby rendering it suitable as a reversible CO2 chemisorbent or as a support for the preparation of dual-function materials.
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Affiliation(s)
- Anastasios
I. Tsiotsias
- Laboratory
of Alternative Fuels and Environmental Catalysis (LAFEC), Department
of Chemical Engineering, University of Western
Macedonia, Kozani GR-50100, Greece
- Center
for Catalysis and Separations, Khalifa University
of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Amvrosios G. Georgiadis
- Laboratory
of Alternative Fuels and Environmental Catalysis (LAFEC), Department
of Chemical Engineering, University of Western
Macedonia, Kozani GR-50100, Greece
| | - Nikolaos D. Charisiou
- Laboratory
of Alternative Fuels and Environmental Catalysis (LAFEC), Department
of Chemical Engineering, University of Western
Macedonia, Kozani GR-50100, Greece
| | - Aseel G. S. Hussien
- Center
for Catalysis and Separations, Khalifa University
of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
- Department
of Mechanical Engineering, Khalifa University
of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Aasif A. Dabbawala
- Center
for Catalysis and Separations, Khalifa University
of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
- Department
of Mechanical Engineering, Khalifa University
of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Kyriaki Polychronopoulou
- Center
for Catalysis and Separations, Khalifa University
of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
- Department
of Mechanical Engineering, Khalifa University
of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Maria A. Goula
- Laboratory
of Alternative Fuels and Environmental Catalysis (LAFEC), Department
of Chemical Engineering, University of Western
Macedonia, Kozani GR-50100, Greece
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Ajjaq A, Bulut F, Ozturk O, Acar S. Advanced NH 3 Detection by 1D Nanostructured La:ZnO Sensors with Novel Intrinsic p-n Shifting and Ultrahigh Baseline Stability. ACS Sens 2024; 9:895-911. [PMID: 38293781 DOI: 10.1021/acssensors.3c02256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Due to its stability, transportability, and ability to be produced using renewable energy sources, NH3 has become an attractive option for hydrogen production and storage. Detecting NH3 is then essential, being a toxic and flammable gas that can pose dangers if not properly monitored. ZnO chemiresistive sensors have shown great potential in real NH3 monitoring applications; yet, research and development in this area are ongoing due to reported limitations, like baseline instabilities and sensitivity to environmental factors, including temperature, humidity, and interferent gases. Herein, we suggest an approach to obtain sensors with competitive performance based on ZnO semiconducting metal oxides. For this purpose, one-dimensional nanostructured pure and La-doped ZnO films were synthesized hydrothermally. Incorporating large rare earth ions, like La, into the bulk lattice of ZnO is challenging and can lead to surface defects that are influential in gas-sensing reactions. The sensors experienced a temperature-induced p-n shifting at about 100 °C, verified by the Hall effect and AC impedance measurements. The doped sensor showed exceptional stepwise baseline stability and outstanding performance at a relatively low operating temperature (150 °C) with a sensing response of 91 at best (@ 50 ppm NH3) and recorded a tolerance to water vapor up to 70% RH. Alongside p-n shifting, the enhanced performance was discussed in correlation with La doping-triggered changes in the nanostructural and surfacial properties of the films. We validated the proposed technique by producing similar sensors and performing multiple replicates to ensure consistency and reproducibility. We also introduced the fill factor concept into the gas sensor field as a new trustworthy parameter that could improve sensor performance assessment and help rate sensors based on deviation from ideality.
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Affiliation(s)
- Ahmad Ajjaq
- Department of Physics, Faculty of Science, Gazi University, Ankara 06500, Turkey
| | - Fatih Bulut
- Scientific and Technological Research Applications and Research Center, Sinop University, Sinop 57000, Turkey
| | - Ozgur Ozturk
- Department of Electric and Electronics Engineering, Faculty of Engineering and Architecture, Kastamonu University, Kastamonu 37000, Turkey
| | - Selim Acar
- Department of Physics, Faculty of Science, Gazi University, Ankara 06500, Turkey
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Abdulhamid ZM, Dabbawala AA, Delclos T, Straubinger R, Rueping M, Polychronopoulou K, Anjum DH. Synthesis, characterization, and preliminary insights of ZnFe 2O 4 nanoparticles into potential applications, with a focus on gas sensing. Sci Rep 2023; 13:19705. [PMID: 37952034 PMCID: PMC10640627 DOI: 10.1038/s41598-023-46960-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 11/07/2023] [Indexed: 11/14/2023] Open
Abstract
This work presents a hydrothermal-based facile method for synthesizing ZnFe2O4, whose size can be controlled with the concentration of sodium acetate used as a fuel and its physical changes at nanoscales when exposed to two different gases. The structural, morphological, compositional, and electronic properties of the synthesized samples are also presented in this paper. The crystal structure of the synthesized samples was determined using an X-ray Diffractometer (XRD). The results revealed fluctuations in the size, lattice parameter, and strain in the nanoparticles with increasing the concentration of sodium acetate. Field-Emission Scanning Electron Microscopy (FESEM) was used to determine synthesized materials' morphology and particle size. It revealed that the particles possessed approximately spherical morphology whose size decreased significantly with the increasing amount of sodium acetate. Transmission Electron Microscopy (TEM) was utilized to determine the structure, morphology, and elemental distributions in particles at the nanoscale, and it confirmed the findings of XRD and FESEM analyses. The high-resolution TEM (HRTEM) imaging analysis of the nanoparticles in our studied samples revealed that the particles predominantly possessed (001) type facets. X-ray photoelectron spectroscopy (XPS) and core-loss electron energy loss spectroscopy (EELS) showed an increasing fraction of Fe2+ with the decreasing size of the particles in samples. The Brunauer, Emmett, and Tellers (BET) analysis of samples revealed a higher surface area as the particle size decreases. In addition, the determined surface area and pore size values are compared with the literature, and it was found that the synthesized materials are promising for gas-sensing applications. The ab initio calculations of the Density of States (DOS) and Band structure of (001) surface terminating ZnFe2O4 were carried out using Quantum Espresso software to determine the bandgap of the synthesized samples. They were compared to their corresponding experimentally determined bandgap values and showed close agreement. Finally, in-situ TEM measurement was carried out on one of the four studied samples with robust properties using Ar and CO2 as reference and target gases, respectively. It is concluded from the presented study that the size reduction of the ZnFe2O4 nanoparticles (NPs) tunes the bandgap and provides more active sites due to a higher concentration of oxygen vacancies. The in-situ TEM showed us a nanoscale observation of the change in one of the crystal structure parameters. The d spacing of ZnFe2O4 NPs showed a noticeable fluctuation, reaching more than 5% upon exposure to CO2 and Ar gases.
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Affiliation(s)
- Zeyad M Abdulhamid
- Department of Physics, Center for Catalysis and Separations (CeCaS Center), Khalifa University of Science and Technology, Abu Dhabi, 127788, United Arab Emirates
| | - Aasif A Dabbawala
- Department of Mechanical Engineering, Center for Catalysis and Separations (CeCaS Center), Khalifa University of Science and Technology, Abu Dhabi, 127788, United Arab Emirates
| | - Thomas Delclos
- Manager, Materials, and Surface Core Labs, Khalifa University of Science and Technology, Abu Dhabi, 127788, United Arab Emirates
| | - Rainer Straubinger
- Core Technology Platforms, New York University Abu Dhabi, Abu Dhabi, 129188, United Arab Emirates
| | - Magnus Rueping
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology, 23955-6900, Thuwa, Saudi Arabia
| | - Kyriaki Polychronopoulou
- Department of Mechanical Engineering, Center for Catalysis and Separations (CeCaS Center), Khalifa University of Science and Technology, Abu Dhabi, 127788, United Arab Emirates
| | - Dalaver H Anjum
- Department of Physics, Center for Catalysis and Separations (CeCaS Center), Khalifa University of Science and Technology, Abu Dhabi, 127788, United Arab Emirates.
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He R, Wang Z, Deng F, Li X, Peng Y, Deng Y, Zou J, Luo X, Liu X. Tunable Bi-bridge S-scheme Bi2S3/BiOBr heterojunction with oxygen vacancy and SPR effect for efficient photocatalytic reduction of Cr(VI) and industrial electroplating wastewater treatment. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2023.123176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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