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O2-evoluting nanoparticles

André E Nogueira, Jéssica A Oliveira, Gelson T S T da Silva, Caue Ribeiro
The CO2 photoreduction process to produce light hydrocarbons is known to be influenced by the presence of CuO nanoparticles, but the actual role of this material, whether as a catalyst or a reactant, has not yet been revealed. In this work, we investigate the role of CuO nanoparticles produced by a solvothermal method as a catalyst in CO2 -saturated water reaction media under UV light, considering the effects of different electrolytes (Na2 C2 O4 , KBrO3 , and NaOH) and temperatures on nanoparticle phase and activity...
February 4, 2019: Scientific Reports
Utpal Kayal, Bishnupad Mohanty, Piyali Bhanja, Sauvik Chatterjee, Debraj Chandra, Michikazu Hara, Bikash Kumar Jena, Asim Bhaumik
In recent years, several novel strategies for speeding up the slow kinetics of the water oxidation reaction have attracted considerable attention for generation of O2. This is particularly important from the environmental perspective. Here we report a SBA-15 type, 2D-hexagonal functionalized mesoporous organosilica material as support for small Ag nanoparticles (NPs) by grafting the silica surface with 3-aminopropyltriethoxysilane, followed by chemical impregnation of Ag NPs at its surface, to obtain a AgNPs@SBA-NH2 material...
January 25, 2019: Dalton Transactions: An International Journal of Inorganic Chemistry
Guoyu Shi, Hiroshi Yano, Donald A Tryk, Shinji Nohara, Hiroyuki Uchida
We, for the first time, demonstrate high electrocatalytic activity for the hydrogen evolution reaction (HER) on PtFe alloy nanoparticles with stabilized Pt-skin layers supported on carbon black (PtxAL-PtFe/C), which allows the reduction of Pt loading to be lowered to 1/20 compared with a conventional Pt black cathode in proton exchange membrane water electrolysis (PEMWE). The area-specific HER activity of PtxAL-PtFe/C was found to be ca. 2 times higher than that of commercial Pt/C at 80 °C and -0.02 V vs. RHE...
January 25, 2019: Physical Chemistry Chemical Physics: PCCP
Adrian Chmielewski, Jun Meng, Beien Zhu, Yi Gao, Hazar Guesmi, Hélène Prunier, Damien Alloyeau, Guillaume Wang, Catherine Louis, Laurent Delannoy, Pavel Afanasiev, Christian Ricolleau, Jaysen Nelayah
Despite intensive research efforts, the nature of the active sites for O2 and H2 adsorption/dissociation by supported gold nanoparticles (NPs) is still an unresolved issue in heterogeneous catalysis. This stems from the absence of a clear picture of the structural evolution of Au NPs at near reaction conditions, i.e. at high pressures and high temperatures. We hereby report real-space observations of the equilibrium shapes of titania-supported Au NPs under O2 and H2 at atmospheric pressure using gas transmission electron microscopy...
January 8, 2019: ACS Nano
Bojie Yuan, Minghao Sui, Jie Qin, Jingyu Wang, Hongtao Lu
Understanding the interaction between silver nanoparticles (Ag NPs) and substances in aquatic systems enables Ag NPs to be better applied in science and industry. Moreover, it also could help us to determine the fate of Ag NPs and assess their hazards in aquatic environment. In this work, the interaction of Ag NPs with HCO3 - , ubiquitous ligand in aquatic systems, during long-term incubation was firstly studied and the possible mechanism was proposed. Results showed that the long-term incubation with HCO3 - led to the red-shifting of UV-vis spectra, the increasing of particles zeta potential (more negative), and the declining of the aqueous Ag+ concentration, as well as the decreasing in the toxicity of Ag NPs suspensions...
December 15, 2018: Journal of Colloid and Interface Science
Lisa M Utschig, Sarah R Soltau, Karen L Mulfort, Jens Niklas, Oleg G Poluektov
Nature's solar energy converters, the Photosystem I (PSI) and Photosystem II (PSII) reaction center proteins, flawlessly manage photon capture and conversion processes in plants, algae, and cyanobacteria to drive oxygenic water-splitting and carbon fixation. Herein, we utilize the native photosynthetic Z-scheme electron transport chain to drive hydrogen production from thylakoid membranes by directional electron transport to abiotic catalysts bound at the stromal end of PSI. Pt-nanoparticles readily self-assemble with PSI in spinach and cyanobacterial membranes as evidenced by light-driven H2 production in the presence of a mediating electron shuttle protein and the sacrificial electron donor sodium ascorbate...
December 7, 2018: Chemical Science
Shumaila Ibraheem, Siguo Chen, Jia Li, Wei Li, XiaoYan Gao, Qingmei Wang, Zidong Wei
The electro-catalyzed oxygen reduction and evolution reactions (ORR/OER) are the key elements of many energy conversion systems, such as fuel cells, water electrolyzers and rechargeable metal-air batteries. Structural design of durable non-noble nanomaterials as bifunctional OER/ORR catalysts is a major drawback to commercial application. Herein, we exposed a strongly coupled hybrid material comprising of NiFeP-cubes nanoparticles supported on three-dimensional interconnected Fe,N-decorated carbon (3D-FeNC) as a robust bifunctional ORR/OER catalyst...
December 13, 2018: ACS Applied Materials & Interfaces
Thomas Altantzis, Ivan Lobato, Annick De Backer, Armand Beche, Yang Zhang, Shibabrata Basak, Mauro Porcu, Qiang Xu, Ana Sánchez-Iglesias, Luis M Liz-Marzán, Gustaaf Van Tendeloo, Sandra Van Aert, Sara Bals
Pt nanoparticles play an essential role in a wide variety of catalytic reactions. The activity of the particles strongly depends on their three-dimensional (3D) structure and exposed facets, as well as on the reactive environment. High resolution electron microscopy has often been used to characterize nanoparticle catalysts, but unfortunately, most observations so far have been either performed in vacuum and/or using conventional (2D) in situ microscopy. The latter however does not provide direct 3D morphological information...
December 12, 2018: Nano Letters
Yuanyuan Guo, Zhengfei Dai, Jun Lu, Xiaoqiao Zeng, Yifei Yuan, Xuanxuan Bi, Lu Ma, Tianpin Wu, Qingyu Yan, Khalil Amine
Low-cost and highly active electrocatalysts are attractive for Li-O2 applications. Herein, a 3D interconnected plate architecture consisting of ultra-small Co-Ni grains embedded in lithium hydroxide nanoplates (Co2Ni@LiOH) is designed and prepared by a lithiation strategy at room temperature. This catalyst exhibits a remarkably reduced charge potential of ~ 3.4 V at 50 µA cm-2, which leads to the high roundtrip efficiency of ~ 79%, among the best levels reported and a cycle life of up to 40 cycles. The well-aligned network facilitates the oxygen diffusion and the electrolyte penetration into the electrode...
December 4, 2018: ACS Applied Materials & Interfaces
Amit Kumar, Anamika Rana, Gaurav Sharma, Mu Naushad, Ala'a H Al-Muhtaseb, Changsheng Guo, Ana Iglesias-Juez, Florian J Stadler
Highly photoresponsive semiconductor photocatalysis for energy and environmental applications require judicious choice and optimization of semiconductor interfaces for wide spectral capabilities. This work aims at rational designing of highly active SrTiO3 /g-C3 N4 junctions bridged with Ag/Fe3 O4 nanoparticles for utilizing Z-scheme transfer and surface plasmon resonance effect of Ag augmented by iron oxide. The SrTiO3 /(Ag/Fe3 O4 )/g-C3 N4 (SFC) catalyst was employed for photocatalytic hydrogen production and photodegradation of levofloxacin (LFC; 20 mg/L) under UV, visible, near infra-red, and natural solar light exhibiting high performance...
November 28, 2018: ACS Applied Materials & Interfaces
Jiaxin Bai, Baichuan Lu, Qing Han, Quan-Song Li, Liangti Qu
Development of a simple and stable photocatalyst for overall water splitting is a promising avenue for solar energy conversion. Here, carbon nitride nanosheets (CN) panel decorated with in situ formed (111) facets-oriented Au nanoparticles (AuNPs) have been prepared by vapor-deposition polymerization (VDP) followed with easy immersion technique. Benefiting from the enhanced visible light absorption, surface plasmon resonance effect of AuNPs, rapid transportation and separation of charge carriers, as well as better aligned valence band levels, the as-obtained photocatalyst shows effective overall water splitting with stoichiometric H2 and O2 evolution even without any sacrificial agent, distinct from the half-reaction of Pt decorated CN...
October 12, 2018: ACS Applied Materials & Interfaces
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 15, 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
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