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O2-evoluting nanoparticles

Soumik Podder, Dipak Chanda, Anoop Kumar Mukhopadhyay, Arnab De, Bhaskar Das, Amalesh Samanta, John George Hardy, Chandan Kumar Ghosh
The toxicity of nanomaterials can sometimes be attributed to photogenerated reactive oxygen species (ROS), but these ROS can also be scavenged by nanomaterials, yielding opportunities for crossover between the properties. The morphology of nanomaterials also influences such features due to defect-induced properties. Here we report morphology-induced crossover between pro-oxidant activity (ROS generation) and antioxidant activity (ROS scavenging) of MgO. To study this process in detail, we prepared three different nanostructures of MgO (nanoparticles, nanoplates, and nanorods) and characterized them by HRTEM...
October 3, 2018: Inorganic Chemistry
M A Edwards, D A Robinson, H Ren, C G Cheyne, C S Tan, H S White
The development of nanoscale electrochemistry since the mid-1980s has been predominately coupled with steady-state voltammetric (i-E) methods. This research has been driven by the desire to understand the mechanisms of very fast electrochemical reactions, by electroanalytical measurements in small volumes and unusual media, including in vivo measurements, and by research on correlating electrocatalytic activity, e.g., O2 reduction reaction, with nanoparticle size and structure. Exploration of the behavior of nanoelectrochemical structures (nanoelectrodes, nanoparticles, nanogap cells, etc...
October 1, 2018: Faraday Discussions
Mohammad Fathi Tovini, Bhushan Patil, Cevriye Koz, Tamer Uyar, Eda Yılmaz
A 3D RuO2 /Mn2 O3 /carbon nanofiber (CNF) composite has been prepared in this study by a facile two step microwave synthesis, as a bi-functional electrocatalyst towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). RuO2 nanoparticles with the mean size of 1.57 nm are uniformly distributed on Mn2 O3 nano-rods grown on electrospun CNFs. The electrocatalytic activity of the composites are investigated towards ORR/OER under alkaline condition. The ternary RuO2 /Mn2 O3 /CNF composite showed superior ORR activity in terms of onset potential (0...
November 23, 2018: Nanotechnology
Yan Zhang, Jingwei Tian, Jing Zhong, Xianming Shi
The rigorous organic and inorganic laminated structure of nacre has been developed by millions of years of biological evolution against various external impacts, including mechanical loadings and chemical attacks. Nacre-biomimetic materials have been recognized as an effective strategy to achieve high strength and toughness simultaneously. However, the understanding of nacre-like structure from the perspective of corrosion protection is still very limited. This work investigates the anticorrosion performance of nacre-biomimetic GO/epoxy (NBGE) coatings with alternating layers...
September 17, 2018: ACS Nano
Huanhuan Li, Mengting Si, Lihua Liu, Xiangqian Chu, Shuai Wang, Lei Wan, Rong Yan, Mengtao Sun, Yingcui Fang
By oxidation of silver nanoparticles (AgNPs) in two ways: thermal oxidation (TO) in molecular oxygen and cool oxidation in oxygen plasma (i.e., oxygen plasma irradiation, OPI), the efficiency and mechanism of visible light-induced selective transformation of 4-aminothiophenol (PATP) to 4,4'-dimercaptoazobenzene (DMAB) on the surface of AgNPs was explored. On the basis of the evolution of surface-enhanced Raman scattering (SERS) spectrum of PATP (10-5 M in ethanol) with the oxidation time, it can be concluded that OPI could improve the selective transformation efficiency (η) effectively, by 87 times for only 2 s; whereas TO could improve η conditionally, increasing at first and then decreasing gradually to zero...
September 25, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Degao Wang, Michael S Eberhart, Matthew V Sheridan, Ke Hu, Benjamin D Sherman, Animesh Nayak, Ying Wang, Seth L Marquard, Christopher J Dares, Thomas J Meyer
Stabilized photoanodes for light-driven water oxidation have been prepared on nanoparticle core/shell electrodes with surface-stabilized donor-acceptor chromophores, a water oxidation catalyst, and an electron-transfer mediator. For the electrode, fluorine-doped tin oxide FTO|SnO2 /TiO2 |-Org1-|1.1 nm Al2 O3 |-RuP2+ -WOC (water oxidation catalyst) with Org1 (1-cyano-2-(4-(diphenylamino)phenyl)vinyl)phosphonic acid), the mediator RuP2+ ([Ru(4,4-(PO3 H2 )2 -2,2-bipyridine)(2,2-bipyridine)2 ]2+ ), and the WOC, Ru(bda)(py(CH2 )(3or10) P(O3 H)2 )2 (bda is 2,2-bipyridine-6,6-dicarboxylate with x = 3 or 10), solar excitation resulted in photocurrents of ∼500 µA/cm2 and quantitative O2 evolution at pH 4...
August 21, 2018: Proceedings of the National Academy of Sciences of the United States of America
Riddhipratim Mandal, Anupriya Baranwal, Ananya Srivastava, Pranjal Chandra
Biosensor designing took a giant leap in its path of evolution after its merger with a wing of nanotechnology. Dramatic properties like high surface area to volume ratio, enhanced chemical and optical properties of nanoscale materials have revolutionized sensor technology in terms of their analytical performance. Many metallic nanoparticles (MeNPs) like gold, silver, platinum, palladium nanoparticles, etc. have been tremendously exploited for improving sensor performance. Over the years, there has been slow but steady shift in nanoscience research with an aim to explore composite MeNPs like bimetallic, trimetallic nanoparticles, etc...
October 15, 2018: Biosensors & Bioelectronics
Haitao Wu, Wang Sun, Junrong Shen, David W Rooney, Zhenhua Wang, Kening Sun
The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are both fundamental and essential processes for various energy conversion and storage systems. The kinetics of ORR and OER play a critical role in their energy efficiency and practicality. Here, flower-like ultrathin Co3O4 nanosheets synthesized through a facile solvothermal technique were studied as a bifunctional catalyst for both water splitting and non-aqueous Li-O2 batteries. Due to the novel structure and highly active {110} and {100} exposed facets, which can effectively facilitate mass transfer and enhance catalytic capability, Co3O4 nanosheets exhibit better stability and higher ORR/OER activity than Co3O4 nanoparticles, Co3O4 bulks, Pt/C, and RuO2 in alkaline solution...
May 31, 2018: Nanoscale
Ahmed Naitabdi, Anthony Boucly, François Rochet, Robert Fagiewicz, Giorgia Olivieri, Fabrice Bournel, Rabah Benbalagh, Fausto Sirotti, Jean-Jacques Gallet
The investigation of nanocatalysts under ambient pressure by X-ray photoelectron spectroscopy gives access to a wealth of information on their chemical state under reaction conditions. Considering the paradigmatic CO oxidation reaction, a strong synergistic effect on CO catalytic oxidation was recently observed on a partly dewetted ZnO(0001)/Pt(111) single crystal surface. In order to bridge the material gap, we have examined whether this inverse metal/oxide catalytic effect could be transposed on supported ZnPt nanocatalysts deposited on rutile TiO2(110)...
April 5, 2018: Nanoscale
Hyun Jik Kim, Young Hun Seo, Sujin An, Ara Jo, Ick Chan Kwon, Sehoon Kim
Rationale: Hydrogen peroxide (H2 O2 ) provides an important mechanism for resisting infectious pathogens within the respiratory tract, and accordingly, the in situ analysis of H2 O2 generation in real time provides a valuable tool for assessing immune response. Methods: In this study, we applied a chemiluminescent nanoparticle-based real-time imaging approach to noninvasive evaluation of the Duox2-mediated H2 O2 generation after viral infection, and assessed its usefulness for analytical purposes in mouse nasal mucosa...
2018: Theranostics
Limin Leng, Jing Li, Xiaoyuan Zeng, Xinlong Tian, Huiyu Song, Zhimin Cui, Ting Shu, Haishui Wang, Jianwei Ren, Shijun Liao
The cycling stability of Li-O2 batteries has been impeded by the lack of high-efficiency, and durable oxygen cathodes for the oxygen-reduction reaction (ORR) and the oxygen-evolution reaction (OER). Herein we report a novel TiN nanorod array-based cathode, which was firstly prepared by growing a TiN nanorod array on carbon paper (CP), and then followed by depositing MnO2 ultrathin sheets or Ir nanoparticles on the TiN nanorods to form well-ordered, three-dimensional (3D), and free-standing structured cathodes: TiN@MnO2 /CP and TiN@Ir/CP...
February 8, 2018: Nanoscale
Houjuan Zhu, Jingchao Li, Xiaoying Qi, Peng Chen, Kanyi Pu
Photodynamic nanotheranostics has shown great promise for cancer therapy; however, its therapeutic efficacy is limited due to the hypoxia of tumor microenvironment and the unfavorable bioavailability of existing photodynamic agents. We herein develop hybrid core-shell semiconducting nanoparticles (SPN-Ms) that can undergo O2 evolution in hypoxic solid tumor to promote photodynamic process. Such oxygenic nanoparticles are synthesized through a one-pot surface growth reaction and have a unique multilayer structure cored and coated with semiconducting polymer nanoparticles (SPNs) and manganese dioxide (MnO2 ) nanosheets, respectively...
January 10, 2018: Nano Letters
Ping Li, Xingyu Chen, Huichao He, Xin Zhou, Yong Zhou, Zhigang Zou
Unprecedented 30-faceted BiVO4 polyhedra predominantly surrounded by {132}, {321}, and {121} high-index facets are fabricated through the engineering of high-index surfaces by a trace amount of Au nanoparticles. The growth of high-index facets results in a 3-5 fold enhancement of O2 evolution from photocatalytic water splitting by the BiVO4 polyhedron, relative to its low-index counterparts. Theory calculations reveal that water dissociation is more energetically favorable on the high-index surfaces than on the low-index (010), (110), and (101) surfaces, which is accompanied by a notable reduction in the overpotential (0...
January 2018: Advanced Materials
Sousan Gholamrezaei, Masoud Salavati-Niasari
The principal focus of this investigation is to prepare the SrMnO3 nanostructures by different chemical methods such as ultrasonic, co-precipitation, microwave, and hydrothermal methods. The influence of calcination temperature, and ultrasound irradiation power, and the presence of surfactant investigated on morphology and size of SrMnO3 nanostructures. As-prepared nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray energy dispersive spectroscopy (EDS) and ultraviolet-visible (UV-Vis) spectroscopy...
January 2018: Ultrasonics Sonochemistry
Shuping Li, Ying Du, Ting He, Yangbin Shen, Chuang Bai, Fandi Ning, Xin Hu, Wenhui Wang, Shaobo Xi, Xiaochun Zhou
Gas-generating catalysis is important to many energy-related research fields, such as photocatalytic water splitting, water electrolysis, etc. The technique of single-nanoparticle catalysis is an effective way to search for highly active nanocatalysts and elucidate the reaction mechanism. However, gas-generating catalysis remains difficult to investigate at the single-nanoparticle level because product gases, such as H2 and O2 , are difficult to detect on an individual nanoparticle. Here, we successfully find that nanobubbles can be used to study the gas-generating catalysis, i...
October 11, 2017: Journal of the American Chemical Society
Qiuyan Jin, Bowen Ren, Dongqi Li, Hao Cui, Chengxin Wang
The utilization of a highly active and robust bifunctional catalyst for simultaneously producing H2 and O2 is still a major challenging issue, which is vital for improving the efficiency of overall water splitting. Herein, we employ a novel plasma-assisted strategy to rapidly and conveniently synthesize the three-dimensional (3D) porous composite nanosheets assembled on monodispersed Co nanoparticles encapsulated in a carbon framework (CoNPs@C) on a carbon cloth. Such a novel 3D hierarchical porous nanosheet improves the exposure and accessibility of active sites as well as ensures high electroconductibility...
September 20, 2017: ACS Applied Materials & Interfaces
Seun Lee, Gwang-Hee Lee, Hack Jun Lee, Mushtaq Ahmad Dar, Dong-Wan Kim
Lithium-oxygen batteries promise high energy densities, but are confronted with challenges, such as high overpotentials and sudden death during discharge-charge cycling, because the oxygen electrode is covered with the insulating discharge product, Li2O2. Here, we synthesized low-cost Fe-based nanocomposites via an electrical wire pulse process, as a hybrid electrocatalyst for the oxygen electrode of Li-O2 batteries. Fe3O4-Fe nanohybrids-containing electrodes exhibited a high discharge capacity (13,890 mA h gc(-1) at a current density of 500 mA gc(-1)), long cycle stability (100 cycles at a current rate of 500 mA gc(-1) and fixed capacity regime of 1,000 mA h gc(-1)), and low overpotential (1...
August 25, 2017: Scientific Reports
Haoyi Li, Shuangming Chen, Haifeng Lin, Xiaobin Xu, Haozhou Yang, Li Song, Xun Wang
Well-designed hybrid materials based on noble metal-free elements have great potential to generate hydrogen (H2 ) and oxygen (O2 ) sustainably via overall water splitting for developing practical energy-related technologies. Herein, an accessible method is presented to synthesize nickel diselenide (NiSe2 ) ultrathin nanowires decorated with amorphous nickel oxide nanoparticles (NiOx NPs) as multifunctional electrocatalysts (NSWANs) for hydrogen and oxygen evolution reaction (HER and OER). The NSWANs exhibit quite low HER and OER overpotentials of 174 and 295 mV, respectively, holding the current density of 20 mA cm(-2) for 24 h continuous operations in alkaline media...
July 26, 2017: Small
A Tanaka, K Teramura, S Hosokawa, H Kominami, T Tanaka
We found that plasmonic Au particles on titanium(iv) oxide (TiO2) act as a visible-light-driven photocatalyst for overall water splitting free from any additives. This is the first report showing that surface plasmon resonance (SPR) in a suspension system effectively induces overall water splitting. Modification with various types of metal nanoparticles as co-catalysts enhanced the evolution of H2 and O2. Among these, Ni-modified Au/TiO2 exhibited 5-times higher rates of H2 and O2 evolution than those of Ni-free Au/TiO2...
April 1, 2017: Chemical Science
Clément Falaise, Harrison A Neal, May Nyman
The fate of U(IV)O2 in the environment in a colloidal form and its dissolution and growth in controlled environments is influenced by organic ligation and redox processes, where both affect solubility, speciation, and transport. Here we investigate U(IV) aqueous speciation from pH 0 to 3 with the glycine (Gly) ligand, the smallest amino acid. We document evolution of the monomeric to the hexameric form from pH 0 to 3 via UV-vis spectroscopy and small-angle X-ray scattering (SAXS). Crystals of the hexamer [U6 O4 (OH)4 (H2 O)6 (HGly)12 ]·12Cl- ·12(H2 O) (U6 ) were isolated at pH 2...
June 5, 2017: Inorganic Chemistry
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