Co-generation of hydroxyl and sulfate radicals via homogeneous and heterogeneous bi-catalysis with the EO-PS-EF tri-coupling system for efficient removal of refractory organic pollutants.

Advanced oxidation processes are commonly considered one of the most effective techniques to degrade refractory organic pollutants, but the limitation of a single process usually makes it insufficient to achieve the desired treatment. This work introduces, for the first time, a highly-efficient coupled advanced oxidation process, namely Electro-Oxidation-Persulfate-Electro-Fenton (EO-PS-EF). Leveraging the EO-PS-EF tri-coupling system, diverse contaminants can be highly efficiently removed with the help of reactive hydroxyl and sulfate radicals generated via homogeneous and heterogeneous bi-catalysis, as certified by radical quenching and electron spin resonance.

Piezoelectric and pyroelectric effects induced by interface polar symmetry.

Interfaces in heterostructures have been a key point of interest in condensed-matter physics for decades owing to a plethora of distinctive phenomena-such as rectification, the photovoltaic effect, the quantum Hall effect and high-temperature superconductivity-and their critical roles in present-day technical devices. However, the symmetry modulation at interfaces and the resultant effects have been largely overlooked. Here we show that a built-in electric field that originates from band bending at heterostructure interfaces induces polar symmetry therein that results in emergent functionalities, including piezoelectricity and pyroelectricity, even though the component materials are centrosymmetric.

High resolution visualization of the redox activity of LiO in non-aqueous media: conformal layer vs. toroid structure.

A strong relationship between the surface structure and the redox activity of LiO is visualized directly using scanning electrochemical cell microscopy, employing a dual-barrel nanopipette containing a unique gel polymer electrolyte. These measurements reveal considerable local heterogeneity with significantly enhanced electrochemical activity at toroidal LiO structures when compared to the conformal layer that is usually formed on the cathode of Li-O batteries.

Nanoscale Electrocatalysis of Hydrazine Electro-Oxidation at Blistered Graphite Electrodes.

There is great interest in finding and developing new, efficient, and more active electrocatalytic materials. Surface modification of highly oriented pyrolytic graphite, through the introduction of surface "blisters", is demonstrated to result in an electrode material with greatly enhanced electrochemical activity. The increased electrochemical activity of these blisters, which are produced by electro-oxidation in HClO, is revealed through the use of scanning electrochemical cell microscopy (SECCM), coupled with complementary techniques (optical microscopy, field emission-scanning electron microscopy, Raman spectroscopy, and atomic force microscopy).

Controlled functionalisation of single-walled carbon nanotube network electrodes for the enhanced voltammetric detection of dopamine.

Voltammetric studies of dopamine (DA) oxidation on pristine and acid-treated single-walled carbon nanotube (SWNT) network electrodes were undertaken in order to investigate both the effect of network density and acid treatment times on the voltammetric characteristics for DA oxidation and the susceptibility of the electrodes to fouling. Through careful control of catalysed chemical vapour deposition growth parameters, multiply interconnected and randomly oriented SWNT networks of two significantly different densities were grown (high density, HD, coverage ≫10 μm length of SWNT per μm(-2) and low density, LD, coverage = 5 (±1) μmSWNTμm(-2)). Acid treatment was performed to provide materials with different electrochemical properties and SWNT coverage, as determined by field emission-scanning electron microscopy, atomic force microscopy and micro-Raman spectroscopy.