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Oxygen evolution nano

Arindam Indra, Taeseup Song, Ungyu Paik
Exploring new materials with high efficiency and durability is the major requirement in the field of sustainable energy conversion and storage systems. Numerous techniques have been developed in last three decades to enhance the efficiency of the catalyst systems, control over the composition, structure, surface area, pore size, and moreover morphology of the particles. In this respect, metal organic framework (MOF) derived catalysts are emerged as the finest materials with tunable properties and activities for the energy conversion and storage...
July 8, 2018: Advanced Materials
Jianbo Zhang, Yang Ding, Cheng-Chien Chen, Zhonghou Cai, Jun Chang, Bijuan Chen, Xinguo Hong, Andrei Fluerasu, Yugang Zhang, Ching-Shun Ku, Dale Brewe, Steve Heald, Hirofumi Ishii, Nozomu Hiraoka, Ku-Ding Tsuei, Wenjun Liu, Zhan Zhang, Yong Q Cai, Genda Gu, Tetsuo Irifune, Ho-Kwang Mao
One challenge in studying high-temperature superconductivity (HTSC) stems from a lack of direct experimental evidence linking lattice inhomogeneity and superconductivity. Here, we apply synchrotron hard X-ray nanoimaging and small-angle scattering to reveal a novel micron-scaled ribbon phase in optimally doped Bi2 Sr2 CaCu2 O8+δ (Bi-2212, with δ = 0.1). The morphology of the ribbon-like phase evolves simultaneously with the dome-shaped TC behavior under pressure. X-ray absorption studies show that the increasing of TC is associated with oxygen-hole redistribution in the CuO2 plan, while TC starts to decrease with pressure when oxygen holes become immobile...
August 2, 2018: Journal of Physical Chemistry Letters
Bowei Zhang, Chaojiang Li, Guang Yang, Kang Huang, Junsheng Wu, Zhong Li, Xun Cao, Dongdong Peng, Shiji Hao, Yizhong Huang
Adoption of bare metal oxides as catalytic materials shows inferior electrochemical activity because of their poor electrical conductivity. Although synthetic strategies for the employment of conductive substrates are well-established, the rational design and fabrication of hollow metal oxides nanostructures on the robust matrix with a high surface area and conductivity remains challenging. In the present research work, a strategy that transforms a metal-organic framework thin layer into a nanostructured CuO/C hollow shell to coat on the 3D nano-dendritic Cu foams as an electrode was successfully developed...
July 18, 2018: ACS Applied Materials & Interfaces
Peng Luan, Ying Zhang, Xiaolong Zhang, Zhijun Li, Ragesh Prathapan, Udo Bach, Jie Zhang
In this study, we report a photoanode consisting of a polymeric/inorganic nanojunction between novel nanostructured 3D C3 N4 nano-networks and BiVO4 substrate. This nanojunction is formed such that 3D C3 N4 nano-networks with a positively charged surface are efficiently anchored on the BiVO4 photoanode with a negatively charged surface. This electrostatic self-assembly can initiate and contribute to an intimate contact at the interfaces, leading to an enhanced photoelectrochemical activity and stability compared with that fabricated by non-electrostatic assembly...
June 19, 2018: ChemSusChem
Srishti Mishra, Md Meraj, Snehanshu Pal
A large-scale molecular dynamics (MD) simulation of nano-indentation was carried out to provide insight into the influence of the Al-Al2 O3 interface on dislocation evolution and deformation behavior of Al substrate coated with Al2 O3 thin film. Adaptive common neighbor analysis (a-CNA), centro-symmetry parameter (CSP) estimation, and dislocation extraction algorithm (DXA) were implemented to represent structural evolution during nano-indentation deformation. The absence of elastic regime was observed in the P-h curve for this simulated nano-indentation test of Al2 O3 thin film coated Al specimen...
June 19, 2018: Journal of Molecular Modeling
P Lettenmeier, J Majchel, L Wang, V A Saveleva, S Zafeiratos, E R Savinova, J-J Gallet, F Bournel, A S Gago, K A Friedrich
A stable and cost effective oxygen evolution reaction (OER) catalyst is crucial for the large-scale market penetration of proton exchange membrane (PEM) water electrolyzers. We show that the synthesis of iridium nanoparticles in either low purity ethanol or water, or in the absence of a surfactant, is detrimental to the electrocatalytic properties of the materials. Adding NaBH4 in excess improves the purity of the catalyst enhancing the OER activity up to 100 A gIr -1 at 1.51 V vs. RHE, the highest value reported so far for high purity Ir nanoparticles...
April 14, 2018: Chemical Science
Chakadola Panda, Prashanth W Menezes, Matthias Driess
The low-temperature synthesis of inorganic materials and their interfaces at the atomic and molecular level provides numerous opportunities for the design and improvement of inorganic materials in heterogeneous catalysis for sustainable chemical energy conversion or other energy-saving areas. Using suitable molecular precursors for functional inorganic nanomaterial synthesis allows for facile control over uniform particle size distribution, stoichiometry, and leads to desired chemical and physical properties...
May 7, 2018: Angewandte Chemie
Xiao-Wen Cao, Qi-Dai Chen, Hua Fan, Lei Zhang, Saulius Juodkazis, Hong-Bo Sun
We report a systematical study on the liquid assisted femtosecond laser machining of quartz plate in water and under different etching solutions. The ablation features in liquid showed a better structuring quality and improved resolution with 1/3~1/2 smaller features as compared with those made in air. It has been demonstrated that laser induced periodic structures are present to a lesser extent when laser processed in water solutions. The redistribution of oxygen revealed a strong surface modification, which is related to the etching selectivity of laser irradiated regions...
April 28, 2018: Nanomaterials
Maciej Gryszel, Mykhailo Sytnyk, Marie Jakešová, Giuseppe Romanazzi, Roger Gabrielsson, Wolfgang Heiss, Eric Daniel Głowacki
Low-cost semiconductor photocatalysts offer unique possibilities for industrial chemical transformations and energy conversion applications. We report that a range of organic semiconductors are capable of efficient photocatalytic oxygen reduction to H2 O2 in aqueous conditions. These semiconductors, in the form of thin films, support a 2-electron/2-proton redox cycle involving photoreduction of dissolved O2 to H2 O2 , with the concurrent photooxidation of organic substrates: formate, oxalate, and phenol. Photochemical oxygen reduction is observed in a pH range from 2 to 12...
April 25, 2018: ACS Applied Materials & Interfaces
Yanmei Sun, Shiwei Wang, Junfeng Niu
Microbes play important roles during river remediation and the interaction mechanism illustration between microorganisms and sewage is of great significance to improve restoration technology. In this study, micro-nano bubble and submerged resin floating bed composite technology (MBSR) was firstly used to restore two black and stinking urban rivers. After restoration, the water pollution indices such as dissolved oxygen (DO), ammonia nitrogen (NH4 + -N), total phosphorous (TP), chemical oxygen demand (CODCr ), water clarity, and the number of facial coliform were significantly improved...
June 2018: Bioresource Technology
Wenqiang Li, Ibrahim Saana Amiinu, Bei Ye, Zhe Wang, Jiawei Zhu, Zongkui Kou, Shichun Mu
Currently, a multicomponent platinum-based alloy has been applied as a promising electrocatalyst to improve catalysis and lower the usage of the noble metal platinum. Herein, a tellurium nanowire (NW)-derived ternary TePtFe nanotube (NT) electrocatalyst has been prepared by the Kirkendall effect. The TePtFe NT formed consists of small single-crystal nanoparticles and voids with an open-end and hollow structure. The TePtFe NT electrocatalyst presents an impressive catalytic activity and stability for both the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER)...
April 25, 2018: ChemSusChem
Surya V Devaguptapu, Sooyeon Hwang, Stavros Karakalos, Shuai Zhao, Shiva Gupta, Dong Su, Hui Xu, Gang Wu
Spinel NiCo2 O4 is considered a promising precious metal-free catalyst that is also carbon-free for oxygen electrocatalysis. Current efforts mainly focus on optimal chemical doping and substituent to tune its electronic structures for enhanced activity. Here, we study its morphology control and elucidate the morphology-dependent catalyst performance for bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Three types of NiCo2 O4 catalysts with significantly distinct morphologies were prepared using temple-free, Pluronic-123 (P-123) soft, and SiO2 hard templates, respectively, via hydrothermal methods followed by calcination...
December 27, 2017: ACS Applied Materials & Interfaces
Gurcan Aral, Md Mahbubul Islam, Adri C T van Duin
Highly reactive metallic nickel (Ni) is readily oxidized by oxygen (O2 ) molecules even at low temperatures. The presence of the naturally resulting pre-oxide shell layer on metallic Ni nano materials such as Ni nanowires (NW) is responsible for degrading the deformation mechanisms and related mechanical properties. However, the role of the pre-oxide shell layer on the metallic Ni NW coupled with the complicated mechanical deformation mechanism and related properties have not yet been fully and independently understood...
December 20, 2017: Physical Chemistry Chemical Physics: PCCP
Matteo Cialone, Federica Celegato, Marco Coïsson, Gabriele Barrera, Gianluca Fiore, Ruslan Shvab, Uta Klement, Paola Rizzi, Paola Tiberto
Multicomponent layered systems with tailored magnetic properties were fabricated via current annealing from homogeneous Fe67 Pd33 thin films, deposited via radio frequency sputtering on Si/SiO2 substrates from composite target. To promote spontaneous nano-structuring and phase separation, selected samples were subjected to current annealing in vacuum, with a controlled oxygen pressure, using various current densities for a fixed time and, as a consequence, different phases and microstructures were obtained...
November 30, 2017: Scientific Reports
Yan Zhang, Yanhui Wang, Chan Han, Shaopei Jia, Shuyu Zhou, Jianbing Zang
Herein, tungsten-coated nano-boron carbide (W-WB4 -WCx /B4 C) particles were prepared by heating a mixture of B4 C and W powder using a spark plasma coating (SPC) method. During the discharge treatment process, metal W in the mixture is activated and reacts with B4 C to form WCx , WB4 , and graphite nanoribbons. The oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance of W-WB4 -WCx /B4 C is tested in an alkaline solution, and the results show that the W-WB4 -WCx /B4 C composite electrocatalyst exhibits a low overpotential of 0...
December 14, 2017: Nanoscale
Dong Un Lee, Moon Gyu Park, Zachary Paul Cano, Wook Ahn, Zhongwei Chen
Nano-engineered hierarchical core-shell nickel cobaltite chestnut-like structures were successfully synthesized as a bifunctionally active electrocatalyst for rechargeable metal-air battery applications. Both the morphology and composition of the catalyst were optimized by a facile hydrothermal reaction, resulting in a 10 h reacted sample demonstrating significantly enhanced activity toward both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in 0.1 m KOH. Specifically, the catalyst demonstrated -0...
January 23, 2018: ChemSusChem
Yanan Jiang, Baodan Liu, Wenjin Yang, Lini Yang, Shujun Li, Xiaoyuan Liu, Xinglai Zhang, Rui Yang, Xin Jiang
Severe environmental contamination and the urgent demand for a clean atmosphere require an efficient and low-cost solution to address problems such as CO emission. In this study, we report the in situ integration of non-noble (Ni1-x Cox )5 TiO7 nanostructures with different Co concentrations and tunable size on a flexible metal network support using a conventional PEO method; we further report their utilization for efficient CO oxidation. It was found that the Co/Ni ratios in the original electrolyte precursors directly result in the different size and morphology evolution...
August 17, 2017: Nanoscale
Karkeng Lim, Muhammad Azmi Abdul Hamid, Roslinda Shamsudin, N H Al-Hardan, Ishak Mansor, Weesiong Chiu
In this paper, we address the synthesis of nano-coalesced microstructured zinc oxide thin films via a simple thermal evaporation process. The role of synthesis temperature on the structural, morphological, and optical properties of the prepared zinc oxide samples was deeply investigated. The obtained photoluminescence and X-ray photoelectron spectroscopy outcomes will be used to discuss the surface structure defects of the prepared samples. The results indicated that the prepared samples are polycrystalline in nature, and the sample prepared at 700 °C revealed a tremendously c-axis oriented zinc oxide...
April 20, 2016: Materials
Jingfang Yu, Qiang Wang, Dermot O'Hare, Luyi Sun
Layered double hydroxides (LDHs) with their highly flexible and tunable chemical composition and physical properties have attracted tremendous attention in recent years. LDHs have found widespread application as catalysts, anion exchange materials, fire retardants, and nano-fillers in polymer nanocomposites. The ability to exfoliate LDHs into ultrathin nanosheets enables a range of new opportunities for multifunctional materials. In this review we summarize the current available LDH exfoliation methods. In particular, we highlight recent developments for the direct synthesis of single-layer LDH nanosheets, as well as the emerging applications of LDH nanosheets in catalyzing oxygen evolution reactions and preparing light emitting devices, supercapacitors, and flame retardant nanocomposites...
October 2, 2017: Chemical Society Reviews
Qinghua Zhang, Xu He, Jinan Shi, Nianpeng Lu, Haobo Li, Qian Yu, Ze Zhang, Long-Qing Chen, Bill Morris, Qiang Xu, Pu Yu, Lin Gu, Kuijuan Jin, Ce-Wen Nan
Oxygen ion transport is the key issue in redox processes. Visualizing the process of oxygen ion migration with atomic resolution is highly desirable for designing novel devices such as oxidation catalysts, oxygen permeation membranes, and solid oxide fuel cells. Here we show the process of electrically induced oxygen migration and subsequent reconstructive structural transformation in a SrCoO2.5-σ film by scanning transmission electron microscopy. We find that the extraction of oxygen from every second SrO layer occurs gradually under an electrical bias; beyond a critical voltage, the brownmillerite units collapse abruptly and evolve into a periodic nano-twined phase with a high c/a ratio and distorted tetrahedra...
July 24, 2017: Nature Communications
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