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Gold nanostructures were fabricated on a transparent indium tin oxide (ITO) coated PET substrate by an electrodeposition technique from a potassium gold (III) chloride solution for two different types of applications. It was found that the optical transparency of lightweight ITO electrodes could be maintained by depositing isolated gold nanostructures while opening up the use of these electrodes for inner sphere electron reactions, such as hydroquinone oxidation, which are not possible at ITO electrodes. For practical applications the adhesion of gold to the ITO electrode was improved by modifying the ITO surface with 3-mercaptopropyl-trimethoxysilane (MPS). Compared to Au/ITO, the Au/MPS/ITO electrode showed vastly improved electrochemical activity toward various electron transfer reactions when subjected to mechanical stress. The biosensing properties of the Au/MPS/ITO electrode was also investigated by studying the detection of immobilized DNA on the Au/MPS/ITO electrode via electrochemical impedance spectroscopy (EIS).

In this work the underpotential deposition of metals such as copper and lead during the electrochemical deposition of gold is investigated to understand the influence that the incorporation of a second metal has on the morphology of gold nanostructures. The incorporation of Pb or Cu, even at concentrations as low as 0.2 %, significantly influence the morphology of the deposit where the formation of elongated structures from a central gold structure is favoured. These nanostructures are characterised by cyclic voltammetry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) and tested for their suitability as a sensing layer for the electrochemical detection of nitrite ions in aqueous solution. A limit of detection of 0.3 µM is achieved with a linear range up to 1 mM which is adequate for the determination of nitrite contained within food products.

Layered transition metal dichalcogenides contain a number of crystal defects which significantly change their properties may be beneficial or detrimental for a specific application. We have prepared defect-rich multiwalled WS2 nanotubes by reductive sulfidization of W18O49 nanowires that were obtained solvothermally from tungsten chloride in different alcohols. The synthesis of the W18O49 nanowires was monitored and their morphological characteristics (e. g. length, rigidity and aspect ratio) are described in detail. The effect of morphology of the nanowires on the synthesis of WS2 nanotubes was investigated in order to obtain WS2 nanotubes that are highly solvent dispersible. Dispersions of the WS2 nanotubes in organic solvents were very stable for several days. The nanotubes could easily be functionalized with noble metals, metal oxides and Janus-type metal@metal oxide nanoparticles. The synthesis of nanowires and nanotubes and the immobilization of the nanoparticles is demonstrated by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) combined with energy dispersive X-ray spectroscopy (EDX), electron diffraction, X-ray diffraction (XRD) and Raman spectroscopy.

The galvanic replacement reaction is a highly versatile approach for the creation of a variety of nanostructured materials. However, the majority of reports are limited to the replacement of metallic nanoparticles or metal surfaces. Here we extend this elegant approach and describe the galvanic replacement of the liquid metal alloy galinstan with Ag and Au. This is achieved at a macrosized droplet to create a liquid metal marble that comprises a liquid metal core and a solid metal shell, whereby the morphology of the outer shell is determined by the concentration of metallic ions used in the solution during the galvanic replacement process. In principle, this allows one to recover precious metal ions from solution in their metallic form, which are immobilized on the liquid metal and therefore easy to recover. The reaction is also undertaken at liquid metal microdroplets created via sonication to produce Ag- and Au-based galinstan nanorice particles. These materials are characterized with SEM, XRD, TEM, SAED, EDX, XPS, UV–visible spectroscopy, and open-circuit potential versus time experiments to understand the galvanic replacement process. Finally, the nanosized materials are investigated for their catalytic activity toward the reduction of methylene blue in the presence of sodium borohydride. This approach illustrates a new avenue of research for the galvanic replacement process and, in principle, could be applied to many more systems.

The ability to detect and monitor toxic and greenhouse gases is highly important, however to achieve this at room temperature and allow for remote sensing applications is a significant challenge. Here, we tackle this issue and investigate conductometric gas sensors that operate at room temperature using a microstructured CuTCNQF4 (TCNQF4 = 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) sensing layer formed via simply immersing an e-beam evaporated Cu film in an acetonitrile solution of TCNQF4. These films were characterized by scanning electron microscopy, Fourier transform infra-red, Raman and X-ray photoelectron spectroscopy. The sensors show a significant response to NO2 and NH3 gases and a negligible response to ethanol at 25°C. Significantly the sensors were tolerant to humidity and a low detection limit of 100 ppb is achieved for NO2 gas.

The application of organic charge-transfer complexes such as TTF-TCNQ (TTF=tetrathiafulvalene, TCNQ=7,7,8,8-tetracyanoquinodimethane) is well known in the area of organic electronics. However, the applicability of this material and its derivatives has not been explored for catalytic reactions. Herein, we report on the catalytic properties of both TTF-TCNQ and the significantly less-known fluorinated analogue TTF-TCNQF4 (TCNQF4=2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane). The model reaction of ferricyanide ion reduction by thiosulfate ions was chosen, for which it was found that both materials were indeed catalytically active. Significantly, the fluorinated TCNQF4 analogue showed considerably higher catalytic activity than TTF-TCNQ. In addition, TTF-TCNQF4 was found to be highly stable under the catalytic conditions and could be recovered and reused without any loss in performance for at least 10 catalytic cycles. This work opens up new avenues for investigating these types of materials for catalytic reactions.

This work reports on the fabrication of a superhydrophobic nylon textile based on the organic charge transfer complex CuTCNAQ (TCNAQ = 11,11,12,12-tetracyanoanthraquinodimethane). The nylon fabric that is metallized with copper undergoes a spontaneous chemical reaction with TCNAQ dissolved in acetonitrile to form nanorods of CuTCNAQ that are intertwined over the entire surface of the fabric. This creates the necessary micro and nanoscale roughness that is required for the Cassie-Baxter state thereby achieving a superhydrophobic/superoleophilic surface without the need for a fluorinated surface. The material is characterised with SEM, FT-IR and XPS spectroscopy and investigated for its ability to separate oil and water in two modes, namely under gravity and as an absorbent. It is found that the fabric can separate dichloromethane, olive oil and crude oil from water and in fact reduce the water content of the oil during the separation process. The fabric is reusable and tolerant to conditions such as seawater, hydrochloric acid and extensive time periods on the shelf. Given that CuTCNAQ is a copper based semiconductor may also open up the possibility of other applications in areas such as photocatalysis and antibacterial applications.