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Maxim Varenik, Xiao-Dong Zhang, Gregory Leitus, Nimrod Yavo, Raanan Carmieli, Ellen Wachtel, Xin Guo, Igor Lubomirsky
The magnetic properties of undoped, bulk CeO2 are not fully understood. In contrast to nanocrystalline ceria that exhibits paramagnetism attributed to Ce3+ at grain surfaces, bulk ceria is weakly paramagnetic, despite the absence of magnetic ions. In the present work, the magnetic susceptibility of bulk ceria ceramics doped with Lu3+, which has neither spin nor orbital angular momentum, was measured in order to assess the relative contributions of the crystal lattice, residual Ce3+ and oxygen vacancies to the overall bulk magnetization...
October 17, 2018: Physical Chemistry Chemical Physics: PCCP
Yi Xu, Chao Wang, Jun Hou, Peifang Wang, Guoxiang You, Lingzhan Miao
In this study, the biofilm formation of Pseudomonas aeruginosa in the presence of cerium oxide nanoparticles (CeO2 NPs) was investigated. With the addition of 0.1 mg/L and 1 mg/L CeO2 NPs, the biofilm development was substantially enhanced. During the attachment process, the enhanced surface hydrophobicity and excess production of mannosan and rhamnolipids in CeO2 NP treatments were detected, which were conductive to the colonization of bacterial cells. During the maturation period, the biofilm biomass was accelerated by the improved aggregation percentage as well as the secretion of extracellular DNA and pyocyanin...
October 15, 2018: Environmental Science and Pollution Research International
Cyren M Rico, Mark G Johnson, Matthew A Marcus, Christian P Andersen
The effects of cerium oxide nanoparticles (CeO2 -NPs) on 15 N/14 N ratio (δ15 N) in wheat and barley were investigated. Seedlings were exposed to 0 and 500 mg CeO2 -NPs/L (Ce-0 and Ce-500, respectively) in hydroponic suspension supplied with NH4 NO3 , NH4 + , or NO3 - . N uptake and δ15 N discrimination (i.e. differences in δ15 N of plant and δ15 N of N source) were measured. Results showed that N content and 15 N abundance decreased in wheat but increased in barley. Ce-500 only induced whole-plant δ15 N discrimination (-1...
July 2018: NanoImpact
Jian Li, Shuyan Song, Yan Long, Shuang Yao, Xin Ge, Lanlan Wu, Yibo Zhang, Xiao Wang, Xiangguang Yang, Hongjie Zhang
By integrating redox self-assembly and redox etching processes, we report a general one-pot strategy for the synthesis of Au@multi-M x O y (M = Co, Ce, Fe, and Sn) yolk@shell nanospheres. Without any additional protecting molecule or reductant, the whole reaction is a clean redox process that happens among the inorganic metal salts in an alkaline aqueous solution. By using this method, Au@Co3 O4 /CeO2 (Au@Co-Ce), Au@Co3 O4 /Fe2 O3 (Au@Co-Fe), and Au@CeO2 /SnO2 (Au@Ce-Sn) yolk@shell nanospheres with binary oxides as shells, Au@Co3 O4 /CeO2 /Fe2 O3 (Au@Co-Ce-Fe) yolk@shell nanospheres with ternary oxides as shells and Au@Co3 O4 /CeO2 /Fe2 O3 /SnO2 (Au@Co-Ce-Fe-Sn) yolk@shell nanospheres with quaternary oxides as shells can be obtained...
October 14, 2018: Chemical Science
Xiaowei Cheng, Le Huang, Xuanyu Yang, Ahmed A Elzatahry, Abdulaziz Alghamdi, Yonghui Deng
Owing to the high costs and instability of natural enzymes, the development of enzyme mimics based on inorganic nanomaterials has attracted a wide concern in recent years. In this work, a stable nanocomposite composed of highly dispersed CeO2 nanoparticles decorated on zeolite Y as support (CeO2 /Y) was synthesized by a facile wet impregnation method, and the CeO2 /Y nanocomposite was firstly proposed as an efficient peroxidase-mimicking nanozyme for accurate detection of H2 O2 and glucose. The best catalyst was the nanocomposite with CeO2 to zeolite Y mass ratio of 0...
September 29, 2018: Journal of Colloid and Interface Science
Lionel Cervera Gontard, Adrián Barroso-Bogeat, Rafal E Dunin-Borkowski, José Juan Calvino
A simple computational method that can be used to simulate TEM image contrast of an electron beam diffracted by a crystal under two-beam dynamical scattering conditions is presented. The approach based on slicing the shape factor is valid for a general crystal morphology, with and without crystalline defects, avoids the column approximation, and provides the complex exit wave at the focal and the image planes also under weak-beam conditions. The approach is particularly efficient for large crystals and the 3D model required for the calculations can be measured experimentally using electron tomography...
September 13, 2018: Ultramicroscopy
Muhammad Ismail, Ijaz Talib, Anwar Manzoor Rana, Tahira Akbar, Shazia Jabeen, Jinju Lee, Sungjun Kim
Memory devices with bilayer CeO2-x /ZnO and ZnO/CeO2-x heterostructures sandwiched between Ti top and Pt bottom electrodes were fabricated by RF-magnetron sputtering at room temperature. N-type semiconductor materials were used in both device heterostructures, but interestingly, change in heterostructure and electroforming polarity caused significant variations in resistive switching (RS) properties. Results have revealed that the electroforming polarity has great influence on both CeO2-x /ZnO and ZnO/CeO2-x heterostructure performance such as electroforming voltage, good switching cycle-to-cycle endurance (~ 102 ), and ON/OFF ratio...
October 11, 2018: Nanoscale Research Letters
Guangjun Zhai, Jinguo Wang, Zimei Chen, Shuaifeng Yang, Yong Men
Three-dimensionally ordered macroporous (3DOM) Co3 O4 -CeO2 catalysts with controllable Co/Ce molar ratios synthesized by colloidal crystal template method were developed to catalyze the NOx -assisted soot oxidation for the first time, and the obtained 3DOM Co3 O4 -CeO2 catalysts exhibited highly enhanced soot oxidation activity. Detailed characterizations of 3DOM Co3 O4 -CeO2 catalysts revealed that the highly enhanced soot oxidation activity was originated from the synergistic promoting effect by combining the macroporous effect resulted from the unique 3DOM framework, the chemical nature associated with more Co3+ reactive sites, the surface enrichment of Ce species and the improved redox properties...
September 24, 2018: Journal of Hazardous Materials
Leila Hasanzadeh, Reza Kazemi Oskuee, Kayvan Sadri, Esmail Nourmohammadi, Mohammad Mohajeri, Zahra Mardani, Alireza Hashemzadeh, Majid Darroudi
AIMS: The in vivo targeted diagnostic applications of biosynthetic Cerium oxide nanoparticles (CeO2 -NPs), prepared by applying chitosan as a stabilizer, was explored by evaluating the cytotoxicity through MTT assay on WEHI 164 cell line, Hemolytic activity of CeO2 -NPs and biodistribution in rats. MAIN METHODS: The CeO2 -NPs were characterized through the use of TGA/DTG, PXRD, FESEM, FTIR, and UV-Vis spectroscopy. The biodistribution of CeO2 -NPs were determined by directly labeled nanoparticles with Technetium-99 m (99mTc) radioisotope (99mTc-CeO2 -NPs)...
October 7, 2018: Life Sciences
Xu Zeng, Jun Liu, Jianfu Zhao
Pharmaceutical sludge is considered as a hazardous material with high treatment and disposal costs. In the present study, the catalytic wet oxidation (CWO) of pharmaceutical sludge by CuO-CeO2/γ-Al2O3 as the catalyst was investigated. The catalyst was prepared by traditional wet impregnation. The catalyst was characterized using X-ray Powder Diffraction (XRD) and Scanning Electron Microscopy (SEM). CWO was performed in an experimental batch reactor. Several parameters that could affect the catalytic degradation efficiency, including catalyst dose, temperature, time, oxygen pressure and pH, were investigated...
2018: PloS One
Xiaolin Guo, Zhihuan Qiu, Jianxin Mao, Renxian Zhou
A series of CuO/CeM(rod) catalysts doped by transition metals were prepared and systematically characterized. The introduction of Mn and Ti plays a significant role in promoting the catalytic performance of the CuO/CeO2(rod) catalyst for the preferential oxidation of CO in H2-rich gas, while the doping with Zr basically maintains the same catalytic activity and Ni leads to a negative influence. Mn and Ti additives remarkably enrich the formation of defect structures and promote copper ion incorporation into the surface of CeM(rod), which greatly facilitates the generation of strong interfacial copper-ceria interaction in CuO/CeMn(rod) and CuO/CeTi(rod)...
October 17, 2018: Physical Chemistry Chemical Physics: PCCP
Leandro Fontanetti Nascimento, Juliana Fonseca Lima, Paulo Cesar de Sousa Filho, Osvaldo Antonio Serra
We report the application of a solid lanthanum-ceria-zinc catalyst in the catalytic regeneration of diesel particulate filters (DPF) in diesel engines. We synthesized a CeO2 -ZnO-La2 O3 (Ce-Zn-La) mixed oxide by a lactic acid-mediated sol-gel method, which efficiently coated cordierite substrates for soot capture and combustion. We studied the effects of La loading on the physicochemical and catalytic properties of Ce-Zn mixed oxide during low-temperature soot combustion processes. We characterized the synthesized catalysts by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), N2 adsorption, Raman spectroscopy, oxygen storage capacity (OSC), and scanning and transmission electron microscopy (SEM and TEM)...
November 2018: Journal of Environmental Sciences (China)
Cristina Artini
Rare-earth (RE)-doped ceria systems, in particular when RE ≡ Nd, Sm, or Gd, are well-known to be characterized by high values of ionic conductivity in the intermediate temperature range, which, in principle, makes them ideal solid electrolytes in solid oxide fuel and electrolysis cells. Defect chemistry turns out to be a pivotal issue in this framework because ionic conductivity is driven by the ability of oxygen vacancies to move through the lattice, and any form of defect clustering tends to depress the efficiency of oxygen transport...
October 5, 2018: Inorganic Chemistry
Lifang Zhang, Junling Meng, Fen Yao, Wenwen Zhang, Xiaojuan Liu, Jian Meng, Hongjie Zhang
Oxygen vacancy (VO ) formation energy and its migration barrier are two determining factors for the effectiveness of solid electrolytes (SEs) in solid oxide fuel cells (SOFCs). In this work, a series of aliovalent rare-earth-doped ceria (Ln x Ce1- x O2-δ , Ln = lanthanides) compounds serving as SEs are comprehensively and comparatively calculated, through which the determinant factors for oxygen vacancy formations and their migration activity are figured out at an atomistic level via the first-principles calculations with the consideration of electronic correlations...
October 2, 2018: Inorganic Chemistry
Zumin Wang, Ranbo Yu
Hollow micro/nanostructured CeO2 -based materials (HMNCMs) have triggered intensive attention as a result of their unique structural traits, which arise from their hollowness and the fascinating physicochemical properties of CeO2 . This attention has led to widespread applications with improved performance. Herein, a comprehensive overview of methodologies applied for the synthesis of various hollow structures, such as hollow spheres, nanotubes, nanoboxes, and multishelled hollow spheres, is provided. The synthetic strategies toward CeO2 hollow structures are classified into three major categories: 1) well-established template-assisted (hard-, soft-, and in situ template) methods; 2) newly emerging self-template approaches, including selective etching, Ostwald ripening, the Kirkendall effect, galvanic replacement, etc...
October 1, 2018: Advanced Materials
Wenge Li, Yanjie Hu, Hao Jiang, Nan Jiang, Wei Bi, Chunzhong Li
Copper-ceria is considered to be a promising system used in exhaust treatment due to its low cost and decent catalytic activity. Herein, we have developed novel litchi-peel-like hollow copper-ceria microspheres with varying Cu contents via an aerosol-assisted route. It is found that the dextrin in the spray solution plays a significant role as a sacrificial template and leads to the formation of this hierarchical hollow structure, in which higher surface area and active CuOx species with higher dispersion result in better catalytic activity compared to the usual hollow samples...
October 1, 2018: Nanoscale
Elif Demir, Serdar Akbayrak, Ahmet M Önal, Saim Özkar
Ruthenium(0) nanoparticles were successfully prepared on the surface of ceria (Ru0 /CeO2 ) and used as catalysts on glassy carbon electrode (GCE) in oxygen evolution reaction (OER) from water electrolysis at room temperature. Ru0 /CeO2 on GCE exhibits high catalytic activity for OER in alkaline solution. It provides a low onset potential of 1.57 V vs. RHE and low overpotential of 420 mV vs. RHE to reach a current density of 10 mA cm-2 . Ru0 /CeO2 on GCE shows no change in the onset potential value even after 6...
September 22, 2018: Journal of Colloid and Interface Science
Xiaodong Hao, Akira Yoko, Chunlin Chen, Kazutoshi Inoue, Mitsuhiro Saito, Gimyeong Seong, Seiichi Takami, Tadafumi Adschiri, Yuichi Ikuhara
Atomic-scale analysis of the cation valence state distribution will help to understand intrinsic features of oxygen vacancies (VO ) inside metal oxide nanocrystals, which, however, remains a great challenge. In this work, the distribution of cerium valence states across the ultrafine CeO2 nanocubes (NCs) perpendicular to the {100} exposed facet is investigated layer-by-layer using state-of-the-art scanning transmission electron microscopy-electron energy loss spectroscopy. The effect of size on the distribution of Ce valence states inside CeO2 NCs is demonstrated as the size changed from 11...
October 2018: Small
Adnan Younis, Sagar E Shirsath, Babar Shabbir, Sean Li
Due to its strong redox ability, high stability, cost effectiveness and non-toxicity, cerium oxide (CeO2 ) has been extensively researched as an active photocatalyst material. The underlying photocatalytic reactions are mostly associated with the transportation of oxygen ions through vacancies, but the actual transport phenomenon had not been clearly understood. In this work, gadolinium (Gd) is sequentially doped into CeO2 to investigate how extrinsic doping can modulate oxygen vacancies in CeO2 and influence photocatalytic activities...
October 21, 2018: Nanoscale
Aisulu Aitbekova, Liheng Wu, Cody J Wrasman, Alexey Boubnov, Adam S Hoffman, Emmett D Goodman, Simon R Bare, Matteo Cargnello
CO2 reduction to higher value products is a promising way to produce fuels and key chemical building blocks while reducing CO2 emissions. The reaction at atmospheric pressure mainly yields CH4 via methanation and CO via the reverse water gas shift (RWGS) reaction. Describing catalyst features that control the selectivity of these two pathways is important to determine the formation of specific products. At the same time, identification of morphological changes occurring to catalysts under reaction conditions can be crucial to tune their catalytic performance...
September 25, 2018: Journal of the American Chemical Society
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