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Adsorption Electrochemistry

Peter A Defnet, Chu Han, Bo Zhang
The hydrogen evolution reaction (HER) was studied on single platinum nanoparticles (NPs) using a microjet NP collision system. By ejecting NPs onto a closely-positioned ultramicroelectrode (UME), one can study single-particle collision electrochemistry in acid concentrations as high as 3 M, or 750 mM on the electrode surface. This is nearly two orders of magnitude greater than previously reported in NP-collision studies. The use of high-bandwidth recording and higher acid concentration allows us to temporally resolve the ultrafast hydrogen adsorption and evolution processes in HER on single colliding Pt NPs...
February 20, 2019: Analytical Chemistry
L L Dong, Y C Ding, W T Huo, W Zhang, J W Lu, L H Jin, Y Q Zhao, G H Wu, Y S Zhang
Recently, graphene decorated with various inorganic nanoparticles, such as Pt, Au, Ag, TiO2 and Fe3 O4 , among which Ag nanocomposites are good candidates for electronics, optics, electrochemistry and catalysis. However, preparation techniques for Ag nanoparticles/carbon matrix hybrids require tedious multi-step processes often involving toxic reducing agents/high temperatures which is not viable for scalable production. Here, a facile, one step and eco-friendly chemical co-reduction route was utilized to synthesis of a new nanocomposites by Ag nanoparticle anchored on reduced graphene oxide (rGO) at ambient temperature and combined first principles theoretical analyze their interfacial adsorption behavior, is reported...
January 4, 2019: Ultrasonics Sonochemistry
Ling Wang, Ran Yang, Jianjun Li, Lingbo Qu, Peter de B Harrington
A new green method for the synthesis of poly(sodium 4-styrenesulfonate) functionalized graphene (PSS-graphene) in aqueous solution was realized by using graphene oxide nanosheets (GO) functionalized with PSS and ascorbic acid (AA) as an reducing agent. Various techniques, including Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and electrochemistry have been utilized to characterize the as-made nanocomposites. The PSS-graphene was used as a modifier to fabricate an electrochemical sensor of tryptophan (Trp)...
May 1, 2019: Talanta
Zhiqiang Sun, Zexu Liu, Yike Xiao, Jiaqi Gong, Shaojie Shuai, Tingting Lang, Chunliu Zhao, Changyu Shen
The electrochemistry (EC) method was used to synthesize graphene oxide-nickel (GO-Ni) metal organic framework (MOF) that has the thickness of μm-level. The MOF's thermal stability and hydrogen adsorption and desorption capacity were measured by using an optical fiber Mach-Zehnder interferometer (MZI) sensor. This MZI was fabricated by core-offset fusion splicing one section of single mode fiber (SMF) between two SMFs. Experimental results showed that the GO-Ni MOF could be stabilized, even as the environmental temperature reached 125 °C...
November 26, 2018: Optics Express
Yinlong Zhu, Hassan A Tahini, Zhiwei Hu, Jie Dai, Yubo Chen, Hainan Sun, Wei Zhou, Meilin Liu, Sean C Smith, Huanting Wang, Zongping Shao
Efficient electrocatalysts for hydrogen evolution reaction are key to realize clean hydrogen production through water splitting. As an important family of functional materials, transition metal oxides are generally believed inactive towards hydrogen evolution reaction, although many of them show high activity for oxygen evolution reaction. Here we report the remarkable electrocatalytic activity for hydrogen evolution reaction of a layered metal oxide, Ruddlesden-Popper-type Sr2 RuO4 with alternative perovskite layer and rock-salt SrO layer, in an alkaline solution, which is comparable to those of the best electrocatalysts ever reported...
January 11, 2019: Nature Communications
Adrian Blidar, Bogdan Feier, Mihaela Tertis, Ramona Galatus, Cecilia Cristea
Surface plasmon resonance technique is highly sensitive to various processes taking place on a metal film and it has emerged as a powerful label-free method to study molecular binding processes taking place on a surface. Another important but less explored area of applications is the use of hybrid methods which combine electrochemistry with optical methods for better monitoring and understanding of biochemical processes. A detection method based on surface plasmon resonance was developed for ampicillin, applying electrochemical techniques for the elaboration and characterization of the aptasensing platform used in this study...
January 9, 2019: Analytical and Bioanalytical Chemistry
Antonio Doménech-Carbó, Fritz Scholz
Dating needs an age-dependent phenomenon (a "clock"), a procedure for monitoring the advance of time by measuring a physicochemical quantity, and, in the case of archeological artifacts, a sampling procedure that guarantees the representativity and integrity of the dated objects. Metal corrosion in an aerobic atmosphere is a phenomenon whose advance can in principle be used as a clock that depends on the environmental conditions. In spite of the limitation imposed by differences in local conditions of corrosion, a new approach for age determinations has been developed and applied as a feasible tool for age determinations of metallic specimens studied by archeologists and historians...
January 7, 2019: Accounts of Chemical Research
Mulugeta B Wayu, Michael J Pannell, Najwa Labban, William S Case, Julie A Pollock, Michael C Leopold
Modified electrodes featuring specific adsorption platforms able to access the electrochemistry of the copper containing enzyme galactose oxidase (GaOx) were explored, including interfaces featuring nanomaterials such as nanoparticles and carbon nanotubes (CNTs). Electrodes modified with various self-assembled monolayers (SAMs) including those with attached nanoparticles or amide-coupled functionalized CNTs were examined for their ability to effectively immobilize GaOx and study the redox activity related to its copper core...
February 2019: Bioelectrochemistry
Fernando Bresme, Oliver Robotham, Weng-I Katherine Chio, Miguel Angel Gonzalez, Alexei Kornyshev
Tetrabutylammonium (TBA) and tetraphenylborate (TPB) ions dissolved in dichloroethane (DCE) are widely used in electrochemistry of liquid-liquid interfaces. Unlike alkali halide solutions in water, TBA-TPB-DCE solutions feature large organic ions and a solvent with a dielectric constant almost one order of magnitude lower than that of water. This is expected to dramatically amplify the impact of ionic correlations in the properties of the solution. Here we report atomistic simulations of TBA-TPB-DCE solutions and analyze ion correlations, clustering, and charge screening effects...
November 7, 2018: Physical Chemistry Chemical Physics: PCCP
Leila Zarei, Roya Tavallaie, Moinul H Choudhury, Stephen G Parker, Padmavathy Bakthavathsalam, Simone Ciampi, Vinicius R Gonçales, J Justin Gooding
Light can be used to spatially resolve electrochemical measurements on a semiconductor electrode. This phenomenon has been explored to detect DNA hybridization with light-addressable potentiometric sensors and, more recently, with light-addressable amperometric sensors based on organic-monolayer-protected Si(100). Here, a contribution to the field is presented by comparing sensing performances when bovine serum albumin (BSA) and hexaethylene glycol (OEG6 ) are employed as antifouling layers that resist nonspecific adsorption to the DNA-modified interface on Si(100) devices...
September 19, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Claudia A Caro-Díaz, Luis Lillo-Arroyo, Francisco J Valenzuela-Melgarejo, Víctor Roudergue-Zúñiga, Gerardo Cabello-Guzmán
This study was conducted to assess the catalytic electrode surface adsorption and capture properties of different metal chitosan derivatives in aqueous phosphate buffer solution (pH = 7.3). Early, recent work showed that the response of Iron chitosan complex with R = -CH3 on the periphery, over blood red cells in presence of sphingomyelinase C was protected. The effect of others substituent (R = -Br, -Cl, -F, NO2 , -OCH3 , -H) on the periphery of the Schiff base ligand did not show correlation with the oxidation of sphingomyelinase C and its biological response...
August 1, 2018: Food and Chemical Toxicology
Zhi Geng, Zhiting Chen, Zhaoyang Li, Xin Qi, Xia Yang, Wei Fan, Yingna Guo, Leilei Zhang, Mingxin Huo
TiO2 nanotubes (TNTs) and AgCl/TiO2 nanotubes (AgCl/TNTs) were synthesized by a hydrothermal method and used in the reduction of nitrate with formic acid as a hole scavenger. As-synthesized photocatalysts were well characterized by field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), N2 adsorption-desorption and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). 5 wt% AgCl/TNTs showed excellent performance in the reduction of nitrate (94...
August 14, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Artur Kasprzak, Magdalena Poplawska
The introduction of cyclodextrin species to graphene-family materials (GFMs) constitutes an important area of research, especially in terms of the development of applied nanoscience. The chemistry of cyclodextrins is the so-called host-guest chemistry, which has impacted on many fields of research, including catalysis, electrochemistry and nanomedicine. Cyclodextrins are water-soluble and biocompatible supramolecules, and therefore they may introduce new interesting properties to GFMs and may enhance the physicochemical/biological features of native GFMs...
August 11, 2018: Chemical Communications: Chem Comm
Gastón D Pierini, Christopher W Foster, Samuel J Rowley-Neale, Héctor Fernández, Craig E Banks
Screen-printed electrodes (SPEs) are ubiquitous with the field of electrochemistry allowing researchers to translate sensors from the laboratory to the field. In this paper, we report an electrochemically driven intercalation process where an electrochemical reaction uses an electrolyte as a conductive medium as well as the intercalation source, which is followed by exfoliation and heating/drying via microwave irradiation, and applied to the working electrode of screen-printed electrodes/sensors (termed EDI-SPEs) for the first time...
July 9, 2018: Analyst
Bo Shen, Xianghua Wen, Gregory V Korshin
Herein, the rotating disk electrode technique was used for the first time to investigate the effects of mass-transfer limitations and pH on the electrochemical oxidation of CPX, to determine the kinetics of CPX oxidation and to explore intrinsic mechanisms during the electron transfer process. Firstly, cyclic voltammetry revealed that an obvious irreversible CPX oxidation peak was observed within the potential window from 0.70 to 1.30 V at all pHs. Based on the Levich equation, the electrochemical oxidation of CPX in the electron transfer process was found to be controlled by both diffusion and kinetic processes when pH = 2, 5, 7 and 9; the diffusion coefficient of CPX at pH = 2 was calculated to be 1...
June 20, 2018: Environmental Science. Processes & Impacts
Craig Jowett, Irina Solntseva, Lingling Wu, Chris James, Susan Glasauer
Clear sand adsorbs 15-35% total phosphorus (P) from septic tank effluent, but P is mobilized when low-P effluent is applied. Amorphous P compounds formed by alkali aluminate chemical addition may also be subject to leaching. Crystalline mineralization is the desired end effect that isolates P thoroughly from the water resource. Using new low-energy iron electrochemistry (EC-P process), dissolved ferrous iron reacts with sewage phosphate ions (PO4 ) and precipitates onto filtration medium as vivianite [Fe3 (PO4 )2 ·8H2 O], as identified by scanning electron microscopy and X-ray diffraction and predicted from Eh-pH-aHPO4 2- phase relations...
May 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Lifu Chen, Eden E L Tanner, Chuhong Lin, Richard G Compton
Graphene nanoplatelets are shown to electrocatalyse the oxidation of dopamine. Single entity measurements ('nano-impacts') coupled with microdisc voltammetry and UV-visible spectroscopy reveal that adsorption of dopamine and its oxidised product on the graphene nanoplatelets is the key factor causing the observed catalysis. Genetic implications are drawn both for the study of catalysts in general and for graphene nanoplatelets in particular.
January 7, 2018: Chemical Science
David Avnir
A unique materials' methodology enables the doping of metals with functional molecules, polymers, enzymes, and nanoparticles. The resulting materials have either the combined properties of the metal and the dopants, or new, sometimes synergetic properties that are not found in the separate components, emerge. Metals that have been doped so far include gold, silver, copper, iron, gallium, palladium, platinum, and several alloys. Numerous applications have been demonstrated including catalysis, biocatalysis, bioactivity, electrochemistry (including new type of batteries), corrosion resistance, induction of chirality, tailoring unconventional properties to metals, and more...
March 12, 2018: Advanced Materials
Lisa M Housel, Lei Wang, Alyson Abraham, Jianping Huang, Genesis D Renderos, Calvin D Quilty, Alexander B Brady, Amy C Marschilok, Kenneth J Takeuchi, Esther S Takeuchi
Future advances in energy storage systems rely on identification of appropriate target materials and deliberate synthesis of the target materials with control of their physiochemical properties in order to disentangle the contributions of distinct properties to the functional electrochemistry. This goal demands systematic inquiry using model materials that provide the opportunity for significant synthetic versatility and control. Ideally, a material family that enables direct manipulation of characteristics including composition, defects, and crystallite size while remaining within the defined structural framework would be necessary...
March 20, 2018: Accounts of Chemical Research
Ana-Maria Chiorcea-Paquim, Teodor Adrian Enache, Ana Maria Oliveira-Brett
Alzheimer's disease (AD) is a widespread form of dementia that is estimated to affect 44.4 million people worldwide. AD pathology is closely related to the accumulation of amyloid beta (Aβ) peptides in fibrils and plagues, the small oligomeric intermediate species formed during the Aβ peptides aggregation presenting the highest neurotoxicity. This review discusses the recent advances on the Aβ peptides electrochemical characterization. The Aβ peptides oxidation at a glassy carbon electrode occurs in one or two steps, depending on the amino acid sequence, length and content...
2018: Current Medicinal Chemistry
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