The development of technologies for the recycling of carbon dioxide into carbon-containing fuels is one of the major challenges in sustainable energy research.
Herein, we report a simple methodology for cleaning Pt nanoparticles, prepared by a colloidal synthesis and coated with polyvinylpyrrolidone, without loss of crystalline surface structure. To prove the removal of the polyvinylpirrolidone from a Pt surface without disturbing the superficial order, a cleaning method using a solution of H(2)O(2)/H(2)SO(4) was tested successfully for a Pt(111) single-crystal electrode. The decontamination method was then tested for two different types of nanoparticles by mixing the suspension of nanoparticles with H(2)O(2)/H(2)SO(4) and subsequent centrifugation. The resulting voltammetric profiles of platinum particles synthesized by the colloidal method employing PVP show a marked presence of the adsorption-state characteristic of (111) ordered surface domains. The presence of the well-ordered domains present on the surface of the nanoparticles was confirmed by using the irreversible adsorption of bismuth, tellurium and germanium.
Electrochemical sensors are powerful tools widely used in industrial, environmental and medical applications. The versatility of electrochemical methods allows for the investigation of chemical composition in real time and in situ. Electrochemical detection of specific biological molecules is a powerful means for detecting disease-related markers. In the last 10 years, highly-sensitive and specific methods have been developed to detect waterborne and foodborne pathogens. In this review, we classify the different electrochemical techniques used for the qualitative and quantitative detection of pathogens. The robustness of electrochemical methods allows for accurate detection even in heterogeneous and impure samples. We present a fundamental description of the three major electrochemical sensing methods used in the detection of pathogens and the advantages and disadvantages of each of these methods. In each section, we highlight recent breakthroughs, including the utilisation of microfluidics, immunomagnetic separation and multiplexing for the detection of multiple pathogens in a single device. We also include recent studies describing new strategies for the design of future immunosensing systems and protocols. The high sensitivity and selectivity, together with the portability and the cost-effectiveness of the instrumentation, enhances the demand for further development in the electrochemical detection of microbes.
Nanoparticle metal oxide photocatalysts are attractive because of their increased reactivity and ease of processing into versatile electrode formats; however, their preparation is cumbersome. We report on the rapid bulk synthesis of photocatalytic nanoparticles with homogeneous shape and size via the cathodic corrosion method, a simple electrochemical approach applied for the first time to the versatile preparation of complex metal oxides. Nanoparticles consisting of tungsten oxide (HWO) nanoplates, titanium oxide (TiO) nanowires, and symmetric star-shaped bismuth vanadate (BiVO) were prepared conveniently using tungsten, titanium, and vanadium wires as a starting material. Each of the particles were extremely rapid to produce, taking only 2-3 min to etch 2.5 mm of metal wire into a colloidal dispersion of photoactive materials. All crystalline HWO and BiVO particles and amorphous TiO were photoelectrochemically active toward the water oxidation reaction. Additionally, the BiVO particles showed enhanced photocurrent in the visible region toward the oxidation of a sacrificial sulfite reagent. This synthetic method provides an inexpensive alternative to conventional fabrication techniques and is potentially applicable to a wide variety of metal oxides, making the rapid fabrication of active photocatalysts with controlled crystallinity more efficient.
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