Ni−Fe (Oxy)hydroxide Modified Graphene Additive Manufactured (3D-Printed) Electrochemical Platforms as an Efficient Electrocatalyst for the Oxygen Evolution Reaction

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim We demonstrate that polylactic acid (PLA)/graphene additive manufactured (3D-printed) electrodes (Gr/AMEs) electrodeposited with Ni−Fe (oxy)hydroxide can efficiently catalyse the oxygen evolution reaction (OER). X-ray photoelectron spectroscopy (XPS) depth profiling combined with Atomic Force Microscopy (AFM) and Tip Enhanced Raman Spectroscopy (TERS) deduced the composition and depth of the Ni−Fe (oxy)hydroxide layer. The composition of the resulting electrocatalytic surfaces are tailored through altering the concentrations of nickel and iron within the electrodeposited solutions, which give rise to optimised AMEs OER performance (within 0.1 M KOH). The optimal OER performance was observed from a Ni−Fe (oxy)hydroxide with a 10 % content of Fe, which displayed an OER onset potential and overpotential of+1.47 V (vs. RHE) and 519 mV, respectively. These values arecomparable to that of polycrystalline Iridium (+ 1.43 V (vs. RHE) and ca. 413 mV), as well as being significantly less electropositive than a bare/unmodified AME. This work is essential for those designing, fabricating and modulating additive manufactured electrodes

Use of Screen-printed Electrodes Modified by Prussian Blue and Analogues in Sensing of Cysteine

© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The utilisation of screen-printing technology allows for a mass scalable approach for the production of electrochemical screen-printed electrodes (SPEs) and the presence of a redox mediator can add new possibilities to the electrochemical properties of the SPEs. Among the materials used as redox mediators, cyanidoferrates polymers can be used for electro-oxidation of cysteine. In this work, two monomers, namely, [Fe(CN) 6 ] 4− and [Fe(CN) 5 NH 3 ] 3− were used to produce Prussian blue (PB) and Prussian blue-Ammine (PB-Ammine), respectively. In addition, two modification methods were compared, firstly via a drop-casting and secondly by the incorporation of these materials into a printable ink. The SPE modified by PB-Ammine (drop-casting) exhibits the highest electroactive area, however the highest heterogeneous rate constant was found with the SPE modified by PB-Ammine that was incorporated into the ink. The highest value of the constant of electro-oxidation of cysteine and lowest limit of detection was also observed in the SPE modified by PB incorporated into the ink. These studies suggest that the electrocatalytic properties of SPE modified by PB and PB-Ammine are dependent upon the availability of Fe 3+ catalytic sites and the increased kinetics of the chemical reaction between the catalytic sites and the analyte

Additive manufacturing electrochemistry: An overview of producing bespoke conductive additive manufacturing filaments

Additive manufacturing represents a state-of-the-art technology that has been extensively disseminated in both the academic and industrial sectors. This technology enables the cost-effective, simple, and automated production of objects with diverse designs. Moreover, within the academic community, additive manufacturing has provided genuine scientific revolutions, particularly in the field of electrochemistry, due to the accessibility of the Fused Filament Fabrication printing methodology, which utilizes thermoplastic filaments for electrochemical platforms. Additive manufacturing has facilitated the production of conductive components for various applications, including electrochemical sensors, batteries, supercapacitors, and electrical circuits. Within recent years, the scientific community has taken an interest in bespoke filaments that are doped with highly conductive particles, which can be optimized and tailored enabling groups to produce a wide range of filaments with uncountable applications. Thus, the present review article explores the distinct methods of bespoke filament manufacturing, emphasizing its significance in the scientific landscape, and investigating the principal materials utilised in its production, such as thermoplastics, plasticizers, and conductive substances, focusing on electrochemistry applications. Furthermore, all reported additive manufacturing methods will be thoroughly discussed, along with their main advantages and disadvantages. Last, future perspectives will be addressed to guide novel advancements and applications of bespoke filaments for use within electrochemistry

Utilising bio-based plasticiser castor oil and recycled PLA for the production of conductive additive manufacturing feedstock and detection of bisphenol A

The production of electrically conductive additive manufacturing feedstocks from recycled poly(lactic acid) (rPLA), carbon black (CB), and bio-based plasticiser castor oil is reported herein. The filament was used to print additively manufactured electrodes (AMEs), which were electrochemically benchmarked against geometrically identical AMEs printed from a commercially available conductive filament. The castor oil/rPLA AMEs produced an enhanced heterogeneous electrochemical rate constant of (1.71 ± 0.22) × 10−3 cm s−1 compared to (0.30 ± 0.03) × 10−3 cm s−1 for the commercial AME, highlighting the improved performance of this filament for the production of working electrodes. A bespoke electroanalytical cell was designed and utilised to detect bisphenol A (BPA). The AMEs made from the castor oil/rPLA gave an enhanced electroanalytical performance compared to the commercial filament, producing a sensitivity of 0.59 μA μM−1, a LOD of 0.10 μM and LOQ of 0.34 μM. This system was then successfully applied to detect BPA in spiked bottled and tap water samples, producing recoveries between 89-104%. This work shows how the production of conductive filaments may be done more sustainably while improving performance

3D-printed immunosensor for the diagnosis of Parkinson's disease

3D printing technology is a strategic tool for the development of electrochemical sensors and biosensors since it is possible to obtain versatile devices quickly and at a low cost. In this work, an arrangement of 3D-printed electrodes (working, pseudo-reference, and auxiliary) was applied for the detection of PARK7/DJ-1 protein in blood serum and cerebrospinal fluid samples. The immunosensor surface was previously chemically and electrochemically activated to promote the increase of the active sites and the conductivity, allowing the covalent immobilization of the biological species (antibodies) and improving its electrochemical performance. The detection was carried out by impedimetric (5.0 −200 µg L−1), and voltammetric measurements (5.0 −500 µg L−1), showing limits of detection of 1.01 and 3.46 µg L−1. The 3D-printed immunosensor also achieved good repeatability and reproducibility from normal to abnormal levels of PARK7/DJ-1 protein, aiming for the diagnosis of Parkinson's disease in different stages of the disease

On the behavior of the carboxyphenylterpyridine(8-quinolinolate) thiocyanatoruthenium(II) complex as a new black dye in TiO2 solar cells modified with carboxymethyl-beta-cyclodextrin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)A terpyridine ligand encompassing a terminal 4-carboxyphenyl group (cptpy), was employed in a new Ru(II) black dye, in the presence of 8-quinolinolate (Q) and SCN- as ancillary ligands. Such compound, here referred as [Ru(cptpy) (Q) (NCS)], was designed aiming its inclusion into carboxymethyl-beta-cyclodextrin, anchored on TiO2. This host-guest strategy was employed to prevent the formation of aggregates and protect the photoinjecting moiety against parallel deactivation events. Such expectation has indeed been fulfilled by the system. On the other hand, 8-quinolinolate as a strong electron donor ligand, effectively enhanced the light harvesting behavior of the dye, shifting and spreading the IPCE peaks over the entire visible region. Unfortunately, the red shift of visible charge-transfer bands was compensated by a decrease of the Ru(III)/(II) potentials, slowing down the electron transfer kinetics with the I-3/I- redox mediator. Therefore, the observed counterbalance between charge transfer energies and redox potentials imposes a critical limit in the design of better mononuclear ruthenium-polypyridine dyes. (C) 2013 Elsevier B.V. All rights reserved.363538Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

A simple method to synthesize fluorescent modified gold nanoparticles using tryptamine as the reducing and capping agent

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)A simple method to synthesize fluorescent modified gold nanoparticles using tryptamine as the reducing and capping agent is described. The presented method produces gold nanoparticles with 36.65 +/- 5.30 nm average size. The modified gold nanoparticles were characterized by elemental and thermal analyses, dynamic light scattering, transmission electron microscopy, zeta potential, X-ray powder diffraction and spectroscopic techniques, such as electronic spectroscopy in ultraviolet-visible and fluorescence excitation-emission. In addition, modified gold nanoparticles were analyzed by solid state N-15 nuclear magnetic resonance spectroscopy, which confirmed the coordination of tryptamine on the gold nanoparticles surface. A prominent characteristic observed is the fluorescence of tryptamine which was not quenched after the coordination to gold nanoparticles. The results presented in this paper confirm the modification of gold nanoparticles by tryptamine and suggest potential use of such nanoparticles as labeling dye in biological systems. (C) 2013 Elsevier B.V. All rights reserved.1856165Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)LNNano (Laboratorio Nacional de Nanotecnologia, Campinas-SP) Brazilian AgencyFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [Proc. 2012/08230-2