Michael Ongaro

Bio: Michael Ongaro is an academic researcher from Ca' Foscari University of Venice. The author has contributed to research in topics: Nanowire & Bipolar electrochemistry. The author has an hindex of 9, co-authored 12 publications receiving 261 citations. Previous affiliations of Michael Ongaro include University of Milan & Merck & Co..

Arrays of copper nanowire electrodes: Preparation, characterization and application as nitrate sensor

Abstract: Ensembles of copper nanowire electrodes (CuWNEEs) are prepared via electrodeposition in track-etched polycarbonate membranes. Three different preparation methods are compared showing that the better results in terms of sensor durability and reproducibility are achieved by pre-sputtering a thin gold film on the templating membrane and attaching it to a supporting electrode by exploiting the adhesion property and ionic conductivity of a thin Nafion interlayer. SEM-EDS analyses together with double layer charging currents measurements indicate that these arrays are formed by copper nanowires with 400 nm diameter, 10 μm length distributed with a spatial density of 1 × 10 8 nanowires/cm 2 . The voltammetric reduction of nitrate at CuWNEEs is characterized by a well-resolved cathodic peak at approximately −0.680 V vs Ag/AgCl, whose current scales linearly with the nitrate concentration in the 10–400 μM range. The limit of detection (LOD) achieved by simple linear sweep voltammetry is in the 1.7–3.0 μM range, depending on the CuWNEE preparation method, such LOD values being among the lowest reported up to now in the literature. The possibility to use CuWNEEs in chloride and nitrite containing water samples is demonstrated.

Bioelectroanalysis with nanoelectrode ensembles and arrays

Abstract: This review deals with recent advances in bioelectroanalytical applications of nanostructured electrodes, in particular nanoelectrode ensembles (NEEs) and arrays (NEAs). First, nanofabrication techniques, principles of function, and specific advantages and limits of NEEs and NEAs are critically discussed. In the second part, some recent examples of bioelectroanalytical applications are presented. These include use of nanoelectrode arrays and/or ensembles for direct electrochemical analysis of pharmacologically active organic compounds or redox proteins, and the development of functionalized nanoelectrode systems and their use as catalytic or affinity electrochemical biosensors.

TiO2-MCM-41 for the photocatalytic abatement of NOx in gas phase

Abstract: Nanotitania supported on mesoporous silica systems were synthesized by a reliable procedure based on an incipient wetness impregnation post-synthetic approach. Characterization by X-ray diffraction, N2 physisorption, TEM, X-ray photoelectron spectroscopy, ICP has been carried out in order to investigate the chemical–physical properties of the catalysts with particular attention to the chemical nature of the titanium species. The photocatalytic activity of the samples was evaluated for the degradation of NOx in the gas phase. The influence of both the textural properties and the nature of titanium species on the photocatalytic activity is discussed.

Closed Bipolar Electrochemistry for the Low‐Potential Asymmetrical Functionalization of Micro‐ and Nanowires

Abstract: We demonstrate the application of closed bipolar electrochemistry for the asymmetrical deposition of metals and metal oxides on bipolar electrodes of decreasing dimensions, down to the nanoscale. We focus on the asymmetrical deposition of semiconducting oxides (TiO2, Cu2O, or Co2O3) and Pt on glassy carbon disks, carbon microwires, and gold nanowires. The optimization of the process is studied by using a four-electrode voltammetric cell. Scanning electron microscopies and energy-dispersive X-ray spectroscopy confirm the achievement of the desired deposition. Electron backscatter diffraction identifies cuprite in all of the Cu2O deposits. Closed bipolar electrochemistry allows the bipolar functionalization of carbon materials and gold nanowires by using electrolytes that are unsuitable for open bipolar electrochemistry, applying a potential difference as low as 1 V. For the first time, Janus like nanosized objects are obtained by closed bipolar electrochemistry.

Removal of NOx by photocatalytic processes

Abstract: The photocatalytic methods for nitrogen oxides removal were recently very intense areas of scientific research. Photo-deNOx processes offer interesting ways for abatement of these harmful gases. This review describes several methods for removing NO by photocatalytic reactions. These methods can be classified into three major groups: photo selective catalytic reduction (photo-SCR), photo-oxidation and photo-decomposition. The application of photocatalysts and photo-processes for NOx abatement in real-scale cases are presented. The fast-growing development of these methods is revealed by the large number of issued patents in photo-deNOx applications. The mechanism of NO creation and the traditional methods (primary and secondary) of NOx removal are summarized and discussed. A cooperative system that combines the traditional (thermal) process and a photo-process is then proposed for improving NOx removal efficiency.

Nanosensors for water quality monitoring

Abstract: Nanomaterial-enabled sensors are being designed for high-efficiency, multiplex-functionality and high-flexibility sensing applications. Many existing nanosensors have the inherent capacity to achieve such goals; however, they require further development into consumer- and operator-friendly tools with the ability to detect analytes in previously inaccessible locations, as well as at a greater scale than heretofore possible. Here, I discuss how nanotechnology-enabled sensors have great, as yet unmet, promise to provide widespread and potentially low-cost monitoring of chemicals, microbes and other analytes in drinking water.

Three-Dimensional Printed Electrode and Its Novel Applications in Electronic Devices

Abstract: Three-dimensional (3D) printing technology provides a novel approach to material fabrication for various applications because of its ability to create low-cost 3D printed platforms. In this study, a printable graphene-based conductive filament was employed to create a range of 3D printed electrodes (3DEs) using a commercial 3D printer. This printing technology provides a simplistic and low-cost approach, which eliminates the need for the ex-situ modification and post-treatment of the product. The conductive nature of the 3DEs provides numerous deposition platforms for electrochemical active nanomaterials such as graphene, polypyrrole, and cadmium sulfide, either through electrochemical or physical approaches. To provide proof-of-concept, these 3DEs were physiochemically and electrochemically evaluated and proficiently fabricated into a supercapacitor and photoelectrochemical sensor. The as-fabricated supercapacitor provided a good capacitance performance, with a specific capacitance of 98.37 Fg−1. In addition, these 3DEs were fabricated into a photoelectrochemical sensing platform. They had a photocurrent response that exceeded expectations (~724.1 μA) and a lower detection limit (0.05 μM) than an ITO/FTO glass electrode. By subsequently modifying the printing material and electrode architecture, this 3D printing approach could provide a facile and rapid manufacturing process for energy devices based on the conceptual design.

Design and engineering heterojunctions for the photoelectrochemical monitoring of environmental pollutants: A review

Abstract: Highly toxic pollutants, e.g. heavy metal ions, phenolics, toxins and pesticides, have posed major threats to ecosystem security and public health. It is imperative to develop simple, low cost, sensitive and reliable techniques for detecting these contaminants in the environment. Compared with traditional analytic techniques, photoelectrochemical (PEC) sensing as a newly emerged approach possesses a low background noise and high sensitivity, opening a new platform for rapid and accurate monitoring of the concerned pollutants. The performance of advanced PEC sensors is fundamentally related to the microstructures and configurations of semiconductor-based photoactive nanomaterials. Therefore, a multidisciplinary research effort focusing on the rational design and synthesis of innovative photoactive nanomaterials has recently emerged. This paper provides a comprehensive review on the engineered semiconductors (i.e. doped-semiconductors) and their heterojunctions (e.g. semiconductor-semiconductor, semiconductor-carbon, semiconductor-metal and multicomponent heterojunction) as well as their emerging applications in PEC sensing and monitoring. Particular attention has been paid to various morphologies, e.g. 0D quantum dots (QDs) and nanoparticles (NPs), 1D nanowires (NWs), nanotubes (NTs) and nanorods (NRs), 2D nanosheets (NSs) and 3D aligned arrays, and their effects on the sensing performances. Moreover, the signal response mechanisms and performance evaluations (e.g. sensitivity, linear range, limit of detection, selectivity and stability) of the constructed PEC sensors are discussed. At last, critical challenges and future research perspectives in the fields are proposed.