The Experts below are selected from a list of 21828 Experts worldwide ranked by ideXlab platform
Mak, Wing Cheung - One of the best experts on this subject based on the ideXlab platform.
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Processable and nanofibrous polyaniline:polystyrene-sulphonate (nano-PANI:PSS) for the fabrication of catalyst-free ammonium sensors and enzyme-coupled urea biosensors
'Elsevier BV', 2021Co-Authors: Uzunçar Sinan, Meng Lingyin, Turner Anthony, Mak, Wing CheungAbstract:Tailoring conducting polymers (CPs) such as polyaniline (PANI) to deliver the appropriate morphology, electrochemical properties and processability is essential for the development of effective polymer-based electrochemical sensors and biosensors. Composite PANI electrodes for the detection of ammonium (NH4+) have been previously reported, but have been limited by their reliance on the Electrocatalytic Reaction between NH4+ and a metal/nano-catalyst. We report an advanced processable and nanofibrous polyaniline:polystyrene-sulphonate (nano-PANI:PSS) as a functional ink for the fabrication of catalyst-free NH4+ sensors and enzyme-coupled urea biosensors. The PSS provides both a soft-template for nanofibre formation and a poly-anionic charge compensator, enabling the detection of NH4+ based on an intrinsic doping/de-doping mechanism. The nanostructured morphology, chemical characteristics and electrochemical properties of the nano-PANI:PSS were characterised. We fabricated 3D-hierarchical sensor interfaces composed of inter-connected nano-PANI:PSS fibres (diameter of similar to 50.3 +/- 4.8 nm) for the detection of NH4+ with a wide linear range of 0.1-11.5 mM (R-2 = 0.996) and high sensitivity of 10(6) mA M-1 cm(-2). We further demonstrated the coupling of the enzyme urease with the nanoPANI:PSS to create a urea biosensor with an innovative biocatalytic product-to-dopant relay mechanism for the detection of urea, with a linear range of 0.2-0.9 mM (R-2 = 0.971) and high sensitivity of 41 mA M-1 cm(-2). Moreover, the nano-PANI:PSS-based sensors show good selectivity for the detection of NH4+ and urea in a urine model containing common interfering molecules. This processable and fibrous nano-PANI:PSS provides new advance on CP-based transducer materials in the emerging field of printed organic sensors and biosensors.Funding Agencies|TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [2214A]
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Processable and nanofibrous polyaniline:polystyrene-sulphonate (nano-PANI:PSS) for the fabrication of catalyst-free ammonium sensors and enzyme-coupled urea biosensors
'Elsevier BV', 2020Co-Authors: Uzunçar Sinan, Meng Lingyin, Turner, Anthony P. F., Mak, Wing CheungAbstract:Tailoring conducting polymers (CPs) such as polyaniline (PANI) to deliver the appropriate morphology, electrochemical properties and processability is essential for the development of effective polymer-based electrochemical sensors and biosensors. Composite PANI electrodes for the detection of ammonium (NH4+) have been previously reported, but have been limited by their reliance on the Electrocatalytic Reaction between NH4+ and a metal/nano-catalyst. We report an advanced processable and nanofibrous polyaniline:polystyrene-sulphonate (nano-PANI:PSS) as a functional ink for the fabrication of catalyst-free NH4+ sensors and enzyme-coupled urea biosensors. The PSS provides both a soft-template for nanofibre formation and a poly-anionic charge compensator, enabling the detection of NH4+ based on an intrinsic doping/de-doping mechanism. The nanostructured morphology, chemical characteristics and electrochemical properties of the nano-PANI:PSS were characterised. We fabricated 3D-hierarchical sensor interfaces composed of inter-connected nano-PANI:PSS fibres (diameter of ~50.3 ± 4.8 nm) for the detection of NH4+ with a wide linear range of 0.1–11.5 mM (R2 = 0.996) and high sensitivity of 106 mA M−1 cm−2. We further demonstrated the coupling of the enzyme urease with the nano-PANI:PSS to create a urea biosensor with an innovative biocatalytic product-to-dopant relay mechanism for the detection of urea, with a linear range of 0.2–0.9 mM (R2 = 0.971) and high sensitivity of 41 mA M−1 cm−2. Moreover, the nano-PANI:PSS-based sensors show good selectivity for the detection of NH4+and urea in a urine model containing common interfering molecules. This processable and fibrous nano-PANI:PSS provides new advance on CP-based transducer materials in the emerging field of printed organic sensors and biosensors
Marc T M Koper - One of the best experts on this subject based on the ideXlab platform.
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analysis of Electrocatalytic Reaction schemes distinction between rate determining and potential determining steps
Journal of Solid State Electrochemistry, 2013Co-Authors: Marc T M KoperAbstract:This paper discusses the concepts of rate-determining step and potential-determining step in the context of Electrocatalytic Reaction schemes, illustrates how the simpler concept of potential-determining step often captures the essence of a bottleneck in a Reaction scheme, and thereby provides straightforward hints for developing better catalysts.
Elizabeth Santos - One of the best experts on this subject based on the ideXlab platform.
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hydrogen evolution and oxidation a prototype for an Electrocatalytic Reaction
Journal of Solid State Electrochemistry, 2009Co-Authors: Elizabeth Santos, A Lundin, K Potting, Paola Quaino, Wolfgang SchmicklerAbstract:Due to progress in the theory of electrocatalysis and in quantum chemistry, it has become possible to investigate the hydrogen Reaction and perform quantitative calculations for the Reaction rate. First, we demonstrate this with model calculations for the adsorption of hydrogen on Pt(111). In accordance with experimental data, we find hydrogen adsorption at a potential above the equilibrium potential and with an almost vanishing energy of activation. As a second example, we explain trends in the catalytic activity of palladium overlayers and clusters on Au(111) electrodes.
Kornienko Nikolay - One of the best experts on this subject based on the ideXlab platform.
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Host-Guest Chemistry Meets Electrocatalysis: Cucurbit[6]uril on a Au Surface as a Hybrid System in CO2 Reduction.
'Organisation for Economic Co-Operation and Development (OECD)', 2020Co-Authors: Wagner Andreas, Ly, Khoa H, Heidary Nina, Szabó István, Földes Tamás, Assaf Khaleel, Barrow, Steven J, Sokołowski Kamil, Al-hada Mohamed, Kornienko NikolayAbstract:The rational control of forming and stabilizing Reaction intermediates to guide specific Reaction pathways remains to be a major challenge in electrocatalysis. In this work, we report a surface active-site engineering approach for modulating Electrocatalytic CO2 reduction using the macrocycle cucurbit[6]uril (CB[6]). A pristine gold surface functionalized with CB[6] nanocavities was studied as a hybrid organic-inorganic model system that utilizes host-guest chemistry to influence the heterogeneous Electrocatalytic Reaction. The combination of surface-enhanced infrared absorption (SEIRA) spectroscopy and Electrocatalytic experiments in conjunction with theoretical calculations supports capture and reduction of CO2 inside the hydrophobic cavity of CB[6] on the gold surface in aqueous KHCO3 at negative potentials. SEIRA spectroscopic experiments show that the decoration of gold with the supramolecular host CB[6] leads to an increased local CO2 concentration close to the metal interface. Electrocatalytic CO2 reduction on a CB[6]-coated gold electrode indicates differences in the specific interactions between CO2 reduction intermediates within and outside the CB[6] molecular cavity, illustrated by a decrease in current density from CO generation, but almost invariant H2 production compared to unfunctionalized gold. The presented methodology and mechanistic insight can guide future design of molecularly engineered catalytic environments through interfacial host-guest chemistry
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Host-Guest Chemistry Meets Electrocatalysis: Cucurbit[6]uril on a Au Surface as a Hybrid System in CO2 Reduction.
'Organisation for Economic Co-Operation and Development (OECD)', 2020Co-Authors: Wagner Andreas, Ly, Khoa H, Heidary Nina, Szabó István, Földes Tamás, Assaf Khaleel, Barrow, Steven J, Sokołowski Kamil, Al-hada Mohamed, Kornienko NikolayAbstract:The rational control of forming and stabilizing Reaction intermediates to guide specific Reaction pathways remains a major challenge in electrocatalysis. In this work, we report a surface active site engineering approach for modulating Electrocatalytic CO2 reduction using the macrocycle cucurbit[6]uril (CB[6]). A pristine gold surface functionalized with CB[6] nanocavities was studied as a hybrid organic-inorganic model system that utilizes host-guest chemistry to influence the heterogeneous Electrocatalytic Reaction. The combination of surface-enhanced infrared absorption (SEIRA) spectroscopy and Electrocatalytic experiments in conjunction with theoretical calculations support capture and reduction of CO2 inside the hydrophobic cavity of CB[6] on the gold surface in aqueous KHCO3 at negative potentials. SEIRA spectroscopic experiments show that the decoration of gold with the supramolecular host CB[6] leads to an increased local CO2 concentration close to the gold interface. Electrocatalytic CO2 reduction on a CB[6]-coated gold electrode indicates differences in the specific interactions between CO2 reduction intermediates within and outside the CB[6] molecular cavity, illustrated by a decrease in CO current density, but almost invariant H2 production compared to unfunctionalized Au. The presented methodology and mechanistic insight will guide future design of molecularly engineered catalytic environments through interfacial host-guest chemistry.Christian Doppler Research Association, the Austrian Federal Ministry for Digital and Economic Affairs, the National Foundation for Research, Technology and Development, the OMV Group, EU ERC Consolidator grant ‘MatEnSAP’, Starting Grant ‘BioNet’, Royal Society Newton International Fellowship, European Commission for Marie Curie Fellowships, EPSRC, DFG, Deutsche Forschungsgemeinschaft/German Research Foundatio
Jeanjacques Delaunay - One of the best experts on this subject based on the ideXlab platform.
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nanoporous cuo layer modified cu electrode for high performance enzymatic and non enzymatic glucose sensing
Nanotechnology, 2015Co-Authors: Changli Li, Mario Kurniawan, Hitoshi Tabata, Jeanjacques DelaunayAbstract:Nanoporous CuO layer on Cu foil with a thick Cu2O interlayer is synthesized via post annealing of previously fabricated Cu(OH)2 nanowires at 500 ?C under an oxygen flow. The formation of the thick sandwiched Cu2O layer is realized through the outward diffusion of Cu ions and subsequent oxidation. An O2 pressure above the dissociation pressure of CuO is used to form a CuO layer at the outer surface of the structure, thus realizing a low cost structure having a porous and high isoelectric point layer. The Cu/Cu2O/CuO structure is used as an efficient electrode for glucose sensing. Sensitivities of at 0.8 V versus Ag/AgCl and 1066 ?A mM?1 cm?2 at 0.6 V versus Ag/AgCl are achieved in an enzymatic and non-enzymatic glucose sensing schemes, respectively. The improved electrochemical sensing ability might be attributed to the efficient Electrocatalytic Reaction on the high crystal quality CuO layer and the porous structure.
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nanoporous cuo layer modified cu electrode for high performance enzymatic and non enzymatic glucose sensing
Nanotechnology, 2015Co-Authors: Mario Kurniawan, Hitoshi Tabata, Dali Sun, Jeanjacques DelaunayAbstract:Nanoporous CuO layer on Cu foil with a thick Cu2O interlayer is synthesized via post annealing of previously fabricated Cu(OH)2 nanowires at 500 °C under an oxygen flow. The formation of the thick sandwiched Cu2O layer is realized through the outward diffusion of Cu ions and subsequent oxidation. An O2 pressure above the dissociation pressure of CuO is used to form a CuO layer at the outer surface of the structure, thus realizing a low cost structure having a porous and high isoelectric point layer. The Cu/Cu2O/CuO structure is used as an efficient electrode for glucose sensing. Sensitivities of [Formula: see text] at 0.8 V versus Ag/AgCl and 1066 μA mM(-1) cm(-2) at 0.6 V versus Ag/AgCl are achieved in an enzymatic and non-enzymatic glucose sensing schemes, respectively. The improved electrochemical sensing ability might be attributed to the efficient Electrocatalytic Reaction on the high crystal quality CuO layer and the porous structure.