Chemical functionalisation of silicon and germanium nanowires

The reduced dimensionality of nanowires implies that surface effects significantly influence their properties, which has important implications for the fabrication of nanodevices such as field effect transistors and sensors. This review will explore the strategies available for wet chemical functionalisation of silicon (Si) and germanium (Ge) nanowires. The stability and electrical properties of surface modified Si and Ge nanowires is explored. While this review will focus primarily on nanowire surfaces, much has been learned from work on planar substrates and differences between 2D and nanowire surfaces will be high-lighted. The possibility of band gap engineering and controlling electronic characteristics through surface modification provides new opportunities for future nanowire based applications. Nano-sensing is emerging as a major application of modified Si nanowires and the progress of these devices to date is discussed

Engineering metallic nanoparticles for enhancing and probing catalytic reactions

Recent developments in tailoring the structural and chemical properties of colloidal metal nanoparticles (NPs) have led to significant enhancements in catalyst performance. Controllable colloidal synthesis has also allowed tailor-made NPs to serve as mechanistic probes for catalytic processes. The innovative use of colloidal NPs to gain fundamental insights into catalytic function will be highlighted across a variety of catalytic and electrocatalytic applications. The engineering of future heterogenous catalysts is also moving beyond size, shape and composition considerations. Advancements in understanding structure-property relationships have enabled incorporation of complex features such as tuning surface strain to influence the behavior of catalytic NPs. Exploiting plasmonic properties and altering colloidal surface chemistry through functionalization are also emerging as important areas for rational design of catalytic NPs. This news article will highlight the key developments and challenges to the future design of catalytic NPs

Does Labour Law Need Philosophical Foundations? (Introduction)

This is the introductory chapter of the book Philosophical Foundations of Labour Law (Collins, Lester, Mantouvalou eds, OUP, 2018). It argues that labour law needs philosophical foundations and explains that careful reflection about underlying moral and political principles and values can serve to provide firm foundations and a clear sense of direction for labour law. At a time when many appear to doubt the value of labour laws and workers’ rights at all, the chapter suggests that it is necessary to reassert that the values and principles that provide the foundations for a system of labour law are not those of a narrow special interest group, but rather embrace interpretations of key values such as freedom, autonomy, dignity, equal respect, democracy, and social justice

Galvanic replacement of sub 20 nm Ag nanoparticles in organic media

Galvanic replacement is a versatile synthetic strategy for the synthesis of alloy and hollow nanostructures. The structural evolution of single crystalline and multiply twinned nanoparticles <20 nm in diameter and capped with oleylamine is systematically studied. Changes in chemical composition are dependent on the size and crystallinity of the parent nanoparticle. The effects of reaction temperature and rate of precursor addition are also investigated. Galvanic replacement of single crystal spherical and truncated cubic nanoparticles follows the same mechanism to form hollow octahedral nanoparticles, a mechanism which is not observed for galvanic replacement of Ag templates in aqueous systems. Multiply twinned nanoparticles can form nanorings or solid alloys by manipulating the reaction conditions. Oleylamine-capped Ag nanoparticles are highly adaptable templates to synthesize a range of hollow and alloy nanostructures with tuneable localised surface plasmon resonance

Embedding colloidal nanoparticles inside mesoporous silica using gas expanded liquids for high loading recyclable catalysts

The ability to tune the structural and chemical properties of colloidal nanoparticles (NPs), make them highly advantageous for studying activity and selectivity dependent catalytic behaviour. Incorporating pre-synthesized colloidal NPs into porous supports materials remains a challenge due to poor wetting and pore permeability. In this report monodisperse, composition controlled AgPd alloy NPs were synthesised and embedded into SBA-15 using supercritical carbon dioxide and hexane. Supercritical fluid impregnation resulted in high metal loading without the requirement for surface pre-treatments. The catalytic activity, reaction profiles and recyclability of the alloy NPs embedded in SBA-15 and immobilised on non-porous SiO2 are evaluated. The NPs incorporated within the SBA-15 porous network showed significantly greater recyclability performance compared to non-porous SiO2

Synthesis and catalytic properties of highly branched palladium nanostructures using seeded growth

In order to develop nanocatalysts with enhanced catalytic performance, it is important to be able to synthesize nanocrystals enclosed by high-index surface facets, due to their high density of low coordinated atoms at step, ledge and kink sites. Here, we report a facile seed-mediated route to the synthesis of highly branched Pd nanostructures with a combination of {113}, {115} and {220} high-index surface planes. The size of these nanostructures is readily controlled by a simple manipulation of the seed concentration. The selective use of oleylamine and oleic acid was also found to be critical to the synthesis of these structures, with Pd icosahedra enclosed by low-index {111} facets being produced when hexadecylamine was employed as capping ligand. The structure–property relationship of these nanostructures as catalysts in Suzuki-cross coupling reactions was then investigated and compared, with the high-index faceted branched Pd nanostructures found to be the most effective catalysts

Palladium-catalyzed coupling reactions for the functionalization of Si surfaces: superior stability of alkenyl monolayers

Palladium-catalyzed Suzuki, Heck, and Sonogashira coupling reactions were studied as reaction protocols for organic modification of Si surfaces. These synthetically useful protocols allow for surface modification of alkene, alkyne, and halide terminated surfaces. Surface oxidation and metal contamination were assessed by X-ray photoelectron spectroscopy. The nature of the primary passivation layer was an important factor in the oxidation resistance of the Si surface during the secondary functionalization. Specifically, the use of alkynes as the primary functionalization layer gave superior stability compared to alkene analogues. The ability to utilize Pd-catalyzed coupling chemistries on Si surfaces opens great versatility for potential molecular and nanoscale electronics and sensing/biosensing applications

Importance Of SBIRT Training In Undergraduate Curriculum

Research poster detailing investigation of the question: What is the significance of Screening, Brief Intervention and Referral to Treatment (SBIRT) and why is it important to implement in undergrad curriculum?https://dune.une.edu/cecespring2020/1000/thumbnail.jp

Peptide synthesis by recombinant Fasciola hepatica cathepsin L1

Synthesis of the tripeptide Z-Phe-Arg-SerNH2 has been accomplished by a recombinant cysteine protease, cathepsin L1 from liver fluke (Fasciola hepatica), using Z-Phe-Arg-OMe as acyl acceptor and SerNH2 as nucleophile in 0.1 M ammonium acetate pH 9.0–12.5% v/v acetonitrile at 37 °C. LC–MS detection indicated tripeptide formation after 10 min, continuing up to 5.5 h. The ester Z-Phe-Arg-OMe was detected throughout the experiment but the hydrolysis product Z-Phe-Arg-OH appeared early and in quite large amounts. We believe that this is the first application of a parasite protease in enzymatic peptide synthesis

2D and 3D photonic crystal materials for photocatalysis and electrochemical energy storage and conversion

This perspective reviews recent advances in inverse opal structures, how they have been developed, studied and applied as catalysts, catalyst support materials, as electrode materials for batteries, water splitting applications, solar-to-fuel conversion and electrochromics, and finally as photonic photocatalysts and photoelectrocatalysts. Throughout, we detail some of the salient optical characteristics that underpin recent results and form the basis for light-matter interactions that span electrochemical energy conversion systems as well as photocatalytic systems. Strategies for using 2D as well as 3D structures, ordered macroporous materials such as inverse opals are summarized and recent work on plasmonic–photonic coupling in metal nanoparticle-infiltrated wide band gap inverse opals for enhanced photoelectrochemistry are provided