bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Anode Channel Depth on Cell Performance in Polymer Electrolyte Membrane Water Electrolyser
Authors: Majasan Jude Olaoluwa , Cho Jason I. S. , Dedigama Ishanka , Shearing Paul R. , Brett Daniel J.L. 
Published: February 2020

The Bipolar/Flow field plate is a vital component of Polymer Electrolyte Membrane Water Electrolysers (PEMWE) which enables electronic conduction, provide mechanical support to the cell and facilitates mass transport of liquid water and produced gases to and from the electrocatalyst surface. From a mass transport viewpoint, especially at high current density operation, optimizing the dimensions and configuration of the flow field plate is crucial to reducing mass transport limitation and achieve improved cell performance. This work investigates the effect of channel depth of the anode flow field plate on performance of a PEM Water Electrolyser using polarization curve and Electrochemical Impedance Spectroscopy technique. A single electrolyser cell with flow field plate having a single straight channel was employed having the channel depth varied from 3.0 mm to 8.0 mm and the cell performance was studied at current densities up to 2 A/cm2. The impedance spectroscopy results show that the effect of channel depth on cell performance is negligible at low and medium current densities, but significant at high current densities. The result indicate that the two-phase flow liquid/gas interactions in the flow channel and the flow regime of operation have a direct influence on mass transport losses and overall performance in the PEM Water Electrolyser. Furthermore, the impedance spectroscopy result at high current densities shows that, generally, deeper channels show better performance than shallower channels which suggests that the effective mass transfer area at the surface of the gas diffusion layer increases with increase in channel depth thus yielding improved mass transport. However, the best performance was observed at 4.5 mm depth which suggests that there exist an optimal channel depth where an increase or decrease in depth would lead to loss of performance. This is attributed to the trade-off between reduced liquid flow velocity and reduced surface coverage of gas bubble/slug in the channel with increasing channel depth in the PEMWE flow field.
Fig 1: Effect of channel depth on cell performance at (a) low, (b) medium and (c) high current density at water flow rate of 40 mL/min and inlet water temperature of 80°C.

Figure 1
(Invited) Carbon Nanomaterials for Flexible and Stretchable Devices
Authors: Zhang Yingying , Wang Huimin , Wang Chunya , Zhang Mingchao 
Published: February 2020

The development of flexible electronics and equipment attracts significant interests in recent years. It is of great importance to develop flexible and wearable energy storage devices for wearable and portable devices. Carbon nanomaterials have large surface area, good conductivity and excellent mechanical and chemical stability, enabling their applications in high performance energy conversion and energy storage devices. In this talk, I will present fiber-shaped ultra-stretchable and flexible supercapacitor made of carbon nanotube fibers, film-shaped stretchable supercapacitors and flexible Zn-air batteries using stretchable graphitized natural fabrics as electrodes. The ultra-stretchable wire-shaped supercapacitor was made by winding two carbon nanotube@graphene@MnO2 fibers around a superelastic core fiber. The supercapacitor can sustain tensile strain up to 850%, which is hitherto the highest value, while keeping stable electrochemical performance. We further demonstrated that there devices can be assembled with carbon-based flexible sensors into wearable smart systems. These strategy paves new ways for the fabrication of high performance wearable energy storage devices and flexible electronics.
References:

Huimin Wang, Chunya Wang, Muqiang Jian, Qi Wang, Kailun Xia, Zhe Yin, Mingchao Zhang, Xiaoping Liang, Yingying Zhang*. Superelastic Wire-shaped Supercapacitor Sustaining 850% Tensile Strain Based on Carbon Nanotube@Graphene Fiber. Nano Research 2017 1007/s12274-017-1782-1

Chunya Wang, Mingchao Zhang, Kailun Xia, Xueqin Gong, Huimin Wang, Zhe Yin, Baolu Guan, and Yingying Zhang*. Intrinsically Stretchable and Conductive Textile by a Scalable Process for Elastic Wearable Electronics. ACS Appl. Mater. Interfaces
2017, 9 (15), 13331–13338.

Mingchao Zhang, Chunya Wang; Xiaoping Liang, Zhe Yin, Kailun Xia, Huimin Wang, Muqiang Jian, Yingying Zhang. Weft-knitted fabric for highly-stretchable and low-voltage wearable heater. Advanced Electronic Materials DOI 10.1002/aelm.201700193

Chunya Wang, Xiao Li, Enlai Gao, Muqiang Jian, Kailun Xia, Qi Wang, Zhiping Xu, Tianling Ren, Yingying Zhang*. Carbonized Silk Fabric for Ultra-stretchable, Highly Sensitive and Wearable Strain Sensors. Advanced Materials 2016, 28, 6640.
Preparation of Polymer-Derived Nitrogen-Doped Hollow Carbon Nanofiber As a Free Standing Oxygen Electrode for Li-O2 Battery
Authors: Lim Katie Heeyum , Kweon Heejun , Kim Hansung 
Published: February 2020

Li-O2 battery has got much attention as a beyond Li-ion battery (LIB), due to its higher energy density and exceeding specific capacity than those of commercial LIB. Though it has a promising potential for large-scale energy storage device, Li-O2 battery still has several problems to be overcome in aspects of poor rate capability and limited stability. Especially, the oxygen electrode is one of the most closely related component to the performance of Li-O2 battery since it is the actual site for formation and decomposition of discharge products. Thus, in order to achieve the Li-O2 battery with improved performance, the oxygen electrode should provide favorable structure for not only discharge product storage, but also facile transfer of reactants such as Li ion and O2. Moreover, bicatalytic activity for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is also significant on oxygen electrode by determining the morphology of discharge product. Furthermore, the oxygen electrode has to be chemically and electrochemically stable as well for extended durability of Li-O2 battery.
In this regards, we develop a binder free oxygen electrode composed of nitrogen-doped hollow carbon nanofiber, which is derived from nitrogen-containing polymer. Each carbon nanofiber has an empty space inside the fiber even after the heat treatment at high temperature of 900 °C, and it can facilitate the mass transfer of reactants. Due to this unique structure and high nitrogen content of 4.5 at. %, nitrogen-doped hollow carbon nanofiber indicates the lower ORR overpotential and larger discharge capacity than commercial carbon material, Super P, as shown in Fig. 1. Interestingly, it shows the reduced ORR/OER overpotential which is lower than 1 V with the curtaining capacity of 500 mAh g-1
carbon. The notably reduced overpotential might be attributable to the synergetic effect of nitrogen doping, unique structure of hollow carbon nanofiber and absence of binder by promoting the catalytic activity, facilitating the mass transfer and suppressing the side reactions, respectively. The effects of heat treatment temperature and metal incorporation are also investigated and optimized. As for the result, it can be demonstrated that the binder-free nitrogen-doped hollow carbon nanofiber is an enhanced oxygen electrode of Li-O2 battery.

Figure 1
Non Noble Metal Catalysts for the Oxygen Reduction Reaction from Mixed MOFs
Authors: Huang Jilin , Lin Zhipeng , Zhan Yunfeng , Meng Hui 
Published: February 2020

Aiming at reducing the cost of fuel cells, the research of non noble metal catalyst has been a hot topic. Recently the performance of non noble metal catalyst has been improved to a level that is similar with noble metal catalyst, leaving the stability a problem to be resolved. The development of non noble metal catalyst has three stages. The first stage is based on porphyrin or phthalocyanine, where nitrogen and iron are from the same precursor. The catalyst is usually pyrolyzed at 400-1000ºC in inert atmosphere [1]；The second stage is characterized by the division of nitrogen and iron precursor, inorganic salt is used as iron precursor and nitrogen containing organic molecular is nitrogen precursor, or inorganic salt is used as iron precursor and NH3 is nitrogen precursor. Both is pyrolyzed at 400-1000ºC in inert atmosphere[2]；The performance of these two kinds of catalysts are poor before the breakthrough made by Pro. Jean-Pol Dodelet from INRS Canada, who improved the MEA performance to 0.26Acm-2 at 0.7V[3]。The performance is then greatly improved at the third stage of non noble metal catalyst, which can be characterized by loading iron salt and nitrogen precursor on MOFs, the pyrolysis is also necessary. The performance of this kind of catalyst is greatly improved. For example the H2/O2 MEA performance of 0.7Acm-2 at 0.7V by Jean-Pol Dodelet[4]; H2/O2 MEA performance of 0.6Acm-2 at 0.7V by Dijia Liu from Argonne National Lab[5]; H2/air MEA performance of 0.3Acm-2 at 0.7V by Sanjeev Mukerjee from Northeastern University6]. In this work we report some recent work of our group in the performance of non noble metal catalyst based on mixed MOFs materials. A preliminary result of H2/O2 MEA performance of 0.2Acm-2 at 0.7V is reached, which is improving.
Figure (a): The ORR performance of the as prepared non noble metal catalyst in O2 saturated 0.1M HClO4 solution at 1600rpm; (b): H2/O2 MEA performance of the as prepared non noble metal catalyst
References:

Jasinski, R., A New Fuel Cell Cathode Catalyst. Nature, 1964. 201(4925): p. 1212-1213.

Jaouen, F., et al., Non-noble electrocatalysts for O-2 reduction: How does heat treatment affect their activity and structure? Part II. Structural changes observed by electron microscopy, Raman, and mass spectroscopy. Journal of Physical Chemistry C, 2007. 111(16): p. 5971-5976.

Lefèvre, M., et al., Iron-Based Catalysts with Improved Oxygen Reduction Activity in Polymer Electrolyte Fuel Cells. Science, 2009. 324(5923): p. 71-74.

Proietti, E., et al., Iron-based cathode catalyst with enhanced power density in polymer electrolyte membrane fuel cells. Nat Commun, 2011. 2: p. 416.

Barkholtz, H.M., et al., Highly Active Non-PGM Catalysts Prepared from Metal Organic Frameworks. Catalysts, 2015. 5(2): p. 955-965.

Li, J., et al., Structural and mechanistic basis for the high activity of Fe-N-C catalysts toward oxygen reduction. Energy & Environmental Science, 2016. 9(7): p. 2418-2432.
Graphene Oxide-Iron Oxide Nanoconjugates for Drug Transport, Biosensing and Bimodal Fluorescence/Magnetic Resonance Imaging
Authors: Gonzalez-Rodriguez Roberto , Sizemore Elizabeth , Naumov Anton V 
Published: February 2020

Due to its remarkable properties, graphene has become a basis of many novel microelectronic devices. However its functional derivatives including graphene oxide (GO) can be mass-produced at lower costs and retain many properties of graphene in addition being water soluble. GO also exhibits fluorescence in the visible/near-IR suitable for applications in optoelectronics and biomedicine. The most novel biomedical applications of GO include, sensing, molecular imaging in visible/near-IR and drug delivery. In all these applications GO was mostly proposed as an agent for in-vitro or ex-vivo imaging due to its emission in visible or near-IR. In this work we combine GO with superparamagnetic iron oxide nanoparticles (Fe3O4 NPs) to provide the unique capacity of multimodal imaging and magnetic targeted drug delivery.
Fe3O4 NPs are biocompatible and have been used as biosensing, magnetic assisted drug delivery system and also a magnetic resonance contrast agent for MRI. Additionally, these NPs can be attracted by a magnet allowing for targeting of the attached therapeutics via the magnetic field to specific organ and/or cancer tumor.
In this work, we fabricate nanoconjugates of GO- Fe3O4 for combining GO fluorescence, sensing and drug delivery properties with magnetic targeting and a possibility of MRI imaging provided by Fe3O4. GO flakes were processed to have diameter mean size of 260 nm optimal for cellular internalization and conjugated to Fe3O4 NPs.
For the specific application of magnetic resonance imaging, the quality of an MRI contrast agent is often evaluated by the relaxivity parameters r1 or r2, which describe the ability of a contrast agent to shorten the T1 or T2 relaxation time of water. GO-Fe3O4 showed suitable for MRI imaging relaxivity values (longitudinal r1 and transvers r2 in water at 37°C), of r1=6.6 mM-1s-1 and r2=71.1 mM-1s-1. In fact, these values are better than those for single Fe3O4 NPs: the conjugated samples showed relaxivity ratio r2/r1>2, placing them in the category of negative contrast agent. The cytotoxicity of GO-Fe3O4 established via MTT assay in HeLa cells showed over 80% viability at the imaging concentrations mimicking that of GO. Cellular uptake and imaging studies show stable internalization and localized emission inside the cells. Additionally this system provides an efficient route to pH sensing of cellular environment as spectra of in GO-Fe3O4 are highly dependent on the pH of the media. This allows to assed the presence of acidic cancerous environments for cancer therapy and detection.
As a result, we propose that this new multifunctional GO-Fe3O4 composite can be used as a magnetic targeted drug delivery system, as well as biosensing and bimodal (MRI and fluorescence) imaging agent.
Optical Properties of Dyes Confined into Carbon and Boron Nitride Nanotubes for Multimodal Bio-Imaging
Authors: Gaufres Etienne , Allard Charlotte , Nascimento Rafaella Oliveira , Fossard Frederic , Flahaut Emmanuel , Loiseau Annick , Martel Richard 
Published: February 2020

Nanotubes attracted a lot of interest as 1D nano-porous materials for the encapsulation and aggregation control of organic dyes molecules. Indeed, the 1D confinement drives the stacking of the molecules inside and enables original aggregation effects on their optical properties (1,2). When encapsulated inside carbon nanotube, organics dyes such as 6T, exhibits for example a strong and specific Raman scattering but their luminescence is efficiently quenched by the nanotube (3). Here we show that the same dyes, when encapsulated inside boron nitride nanotubes (6T@BNNT) exhibits strong luminescence (4). Photoluminescence imaging experiments on individualized 6T@BNNT show that the encapsulation also circumvent the photobleaching issue over days under continuous photo-excitation. Finally we show that these hybrid materials, with specific luminescence and/or Raman fingerprints, can act as robust nanoprobes with reduced toxicity in living system such as Daphnia Pulex, for multimodal imaging from the visible to the near infrared range. (4)
(1) E. Gaufrès et al Nature Photon. (2014)
(2) S. Cambré et al Nature Nano (2015)
(3) E. Gaufrès et al ACS Nano (2016)
(4) E. Gaufrès et al (submitted)
Characterization of Double-Stranded DNA (dsDNA) on Single-Walled Carbon Nanotubes (SWCNTs)
Authors: Wu Shang-Jung , Schuergers Nils , Gillen Alice Judith , Boghossian Ardemis Anoush 
Published: February 2020

DNA has been extensively studied due to its versatility as a dispersant of SWCNTs. The specificity and binding affinity of DNA to various analytes has been shown to be strongly sequence dependent. As a result, through modifications of the nucleotide sequence, the DNA conformation on the SWCNT surface can be tailored to suit specific needs for techniques such as single-molecule detection, in vivo imaging, and chirality separation. To date, the majority of research has focused on the interaction between single-stranded DNA and SWCNT surface, with less focus on the nature of the interaction between double-stranded DNA (dsDNA) and SWCNTs. As a result, the exact interaction mechanism governing this type of complex remains strongly debated and largely unknown.
In this study, we employ various biochemical methods to infer the conformation of dsDNA on the surface of SWCNTs. Our methods are based on imaging techniques for identifying DNA-modifying enzyme activity in the presence of dsDNA-SWCNT complexes. Our findings suggest that dsDNA can partially retain its native conformation on the SWCNT surface, and the degree of dsDNA accessibility is strongly sequence dependent. These findings offer new possibilities for SWCNT sensing applications that employ dsDNA, such as the optical detection of DNA-protein interactions.
(Invited) Nanocarbons for Multimodal Imaging, and Combination Multidrug/Gene Delivery
Authors: Naumov Anton V , Hasan Md Tanvir , Sizemore Elizabeth , Gonzalez-Rodriguez Roberto , Akkaraju Giridhar 
Published: February 2020

Carbon nanomaterials including single-walled carbon nanotubes (SWCNTs) and graphene derivatives serve as a basis of multiple molecular imaging and biological sensing device applications. However, those applications are still mainly centered on a single analyte sensing or the delivery of one particular therapeutic. Structure-dependent band gap configuration of SWCNTs was shown and that of graphene derivatives provides a promise of multiwavelength imaging in near-infrared or visible spectral regions. We utilize these structural characteristics of nanocarbons to provide multidrug delivery and/or multicolor imaging for complex medical conditions requiring combination therapies such as nonalcoholic steatohepatitis (NASH). It is so far, a non-curable condition present in 6-8% of adults in the US. The progression of NASH is mediated mainly via fibrosis and inflammation interlinked through the production of cytokines. The treatment of this complex condition requires targeting of several factors at once. We utilize (6,5) and (7,5) SWCNT samples chirality-separated by aqueous two-phase extraction for the delivery and drug-specific in-vitro imaging of drug and gene therapeutics targeting inflammation and fibrosis. These active agents, each bound non-covalently to SWCNT sample enriched in a specific chirality and purified from the sorting surfactants, are delivered to HepG2 cells and imaged via characteristic SWCNT emission in the near-IR. Hyperspectral microscopy imaging at select wavelengths corresponding to resonant transitions of (6,5) and (7,5) SWCNTs allows to preferentially track the presence of SWCNTs bound to each specific therapeutic. Furthermore, therapeutic effects of each formulation are assessed separately via protein and cytotoxicity assays allowing to utilize remarkable properties of SWCNTs for multimodal imaging and multidrug/gene delivery for NASH therapeutics.
In addition to selective imaging by different SWCNT chiralities we explore multiwavelength biological imaging from the same nanomaterial produced through synthetic modification of nanoscale graphene derivatives and yielding dual-color green/near-IR emission. These fully biocompatible nanocarbons provide efficient internalization and in-vitro imaging in green (530 nm) with higher quantum yields and in near-IR (850 nm) water window region with decreased biological autofluorescence more optimal for ex-vivo and some in-vivo studies. Such new nanocarbon materials build a basis of multipurpose in-vitro/in-vivo multifunctional imaging/delivery agents.
Carbon Nanotubes as Nanovectors for Intracellular Delivery
Authors: DaRos Tatiana 
Published: February 2020

Carbon nanostructures (CNSs) can be efficiently up-taken by cells and this allowed their use as vectors. So with an opportune functionalization it is possible to immobilized on CNSs various compounds, from small molecules till proteins and oligonucleotides, and efficiently deliver those units into cells. The presence of CNSs can ameliorate the efficiency of the uptake, and at the same time can also contribute to protect the delivered molecules from degradation.
We will explore some examples of effective use of CNSs for this purpouse.
(Invited) Assets of Nanodiamonds for Bioapplications
Authors: Arnault Jean-Charles 
Published: February 2020

Diamond nanoparticles (nanodiamonds, NDs) behave physical and chemical properties expected from bulk diamond. Among these assets, their biocompatibility and their versatile surface chemistry based on carbon make them good candidates for bioapplications [1]. Moreover, the high surface to volume ratio of NDs can be tuned with sizes down to 5 nm depending on their synthesis methods [2]. This nanoscale confers new properties to NDs, often governed by their surface chemistry. This small primary size could also ensure a better elimination for in vivo studies. Lastly, the presence of color centers (NV, SiV) in the diamond lattice allow to use fluorescent NDs as biomarkers [3].
After providing the state of art of the synthesis and the current main applications of NDs, this talk will focus on the intrinsic properties of hydrogenated detonation NDs, from surface chemistry to colloidal behavior in water suspensions. Two hydrogenation methods will be compared in terms of hydrogen grafted or incorporated into NDs via isotope studies (3H) [4]. The hydrogenated NDs revealed an ability to produce reactive oxygen species (ROS) in radioresistant human cancer cells under gamma irradiation. This radiosensitive behavior was in vitro demonstrated, turning these cells into senescence state [5]. The physical and chemical mechanisms involved in the production of radicals were investigated by illuminating aqueous colloids of hydrogenated nanodiamonds under X-rays and gamma-rays. An overproduction of hydroxyl radicals and solvated electrons versus water radiolysis was measured using the 7-OH-coumarin as a fluorescent probe [6]. These results well evidence that NDs can act as active nanoparticles under illumination. The main perspectives of NDs for bioapplications will be discussed.

References

[1] K. Turcheniuk and V. N. Mochalin, Biomedical applications of nanodiamond, Nanotechnology 28 (2017) 252001.
[2] O. A. Shenderova, N. Nunn, Production and purification of nanodiamonds in: Nanodiamonds Advanced Material Analysis, Properties and Applications, J. C. Arnault Ed. (Elsevier (2017) pp 25-56.
[3] Y. Y. Hui, L. J. Su, O. Y. Chen, Y. T. Chen, T. M. Liu, H. C. Chang, Wide-field imaging and flow cytometric analysis of cancer cells in blood by fluorescent nanodiamond labeling and time gating, Scientific Reports 4 (2014) 5574.
[4] H.A. Girard, A. El Kharbachi, S. Garcia-Argote, T. Petit, P. Bergonzo, B. Rousseau, J.C. Arnault, Tritium labeling of detonation nanodiamonds. Chem. Comm. 50 (2014) 2916–2918.
[5] R. Grall, H. A. Girard, L. Saad, T. Petit, C. Gesset, M. Combis-Schlumberger, V. Paget, J. Delic, J. C. Arnault, S. Chevillard, Impairing the radioresistance of cancer cells by hydrogenated Nanodiamonds, Biomaterials 61 (2015) 290-298.
[6] M. Kurzyp, H. A. Girard, Y. Cheref, E. Brun, C. Sicard-Roselli, S. Saada, J. C. Arnault, Chem. Commun., 53 (2017) 1237.