Plasmon-based colorimetric assay using green synthesized gold nanoparticles for the detection of bisphenol A.

Herein, we report a green synthesized gold nanoparticle (AuNPs) based colorimetric detection of bisphenol A (BPA). The AuNPs were synthesized using khat leaf extract as a reducing agent by optimizing factors affecting the AuNPs synthesis, including gold precursor concentration (1 mM), and reaction temperature (60 °C). The AuNPs characterization was carried out using ultraviolet-visible spectrophotometry and transmission electron microscopy, and it was found spherical with an average particle size of 17.

Self-assembly of supramolecular nanotubes/microtubes from 3,5-dimethyl-4-iodopyrazole for plasmonic nanoparticle organization.

Hierarchical super-architectures from small molecule self-assembly have interesting properties and play an indispensable role in many fields. In most cases, a self-assembly process refers to multiple intermolecular interactions among intricately designed building blocks. Here, a supramolecular assembly with a tubular morphology with dimensions ranging from nanometers to micrometers was prepared through self-assembly of 3,5-dimethyl-4-iodopyrazole (DMIP), a molecule with an unprecedented simple structure.

Defect Sites in Ultrathin Pd Nanowires Facilitate the Highly Efficient Electrochemical Hydrodechlorination of Pollutants by H*.

Adsorbed atomic H (H*) facilitates indirect pathways playing a major role in the electrochemical removal of various priority pollutants. It is crucial to identify the atomic sites responsible for the provision of H*. Herein, through a systematic study of the distribution of H* on Pd nanocatalysts with different sizes and, more importantly, deliberately controlled relative abundance of surface defects, we uncovered the central role of defects in the provision of H*.

Facile fabrication of silver nanoparticle decorated α-FeO nanoflakes as ultrasensitive surface-enhanced Raman spectroscopy substrates.

Although great progress has been made on designing noble metal nanoparticle aggregates/assemblies as surface-enhanced Raman spectroscopy (SERS) substrates, an ever increasing research interest has focused on fabrication of hierarchical nanostructures for superior SERS performance. Here, we report effective decoration of silver nanoparticles (AgNPs) onto vertically and densely grown α-FeO nanoflakes (NFs) as SERS active substrates. The SERS substrate was prepared by thermally annealing Fe foil at 450 °C to grow α-FeO NFs and electroless deposition of AgNPs onto α-FeO NFs, with excellent ability to control the particle size and density.

Au@Pd Bimetallic Nanocatalyst for Carbon-Halogen Bond Cleavage: An Old Story with New Insight into How the Activity of Pd is Influenced by Au.

AuPd bimetallic nanocatalysts exhibit superior catalytic performance in the cleavage of carbon-halogen bonds (C-X) in the hazardous halogenated pollutants. A better understanding of how Au atoms promote the reactivity of Pd sites rather than vaguely interpreting as bimetallic effect and determining which type of Pd sites are necessary for these reactions are crucial factors for the design of atomically precise nanocatalysts that make full use of both the Pd and Au atoms. Herein, we systematically manipulated the coordination number of Pd-Pd, d-orbital occupation state, and the Au-Pd interface of the Pd reactive centers and studied the structure-activity relationship of Au-Pd in the catalyzed cleavage of C-X bonds.

Transformation and bioavailability of metal oxide nanoparticles in aquatic and terrestrial environments. A review.

Metal oxide nanoparticles (MeO-NPs) are among the most consumed NPs and also have wide applications in various areas which increased their release into the environmental system. Aquatic (water and sediments) and terrestrial compartments are predicted to be the destination of the released MeO-NPs. In these compartments, the particles are subjected to various dynamic processes such as physical, chemical and biological processes, and undergo transformations which drive them away from their pristine state.

Use of Polycrystalline Ice for Assembly of Large Area Au Nanoparticle Superstructures as SERS Substrates.

It is still a great challenge to develop simple and low-cost methods for preparation of surface-enhanced Raman scattering (SERS) substrates with high sensitivity and reproducibility. Taking advantage of the microstructure of polycrystalline ice, we developed a new method to assemble large area gold nanoparticle (AuNP) superstructures as SERS substrates without external templating and aggregating agent. The assembly was conducted by freezing AuNP colloid at -20 °C, which concentrated AuNPs in the ice veins and produced an AuNP superstructure upon thawing the ice.

Ionic liquid-based zinc oxide nanofluid for vortex assisted liquid liquid microextraction of inorganic mercury in environmental waters prior to cold vapor atomic fluorescence spectroscopic detection.

Zinc oxide nanofluid (ZnO-NF) based vortex assisted liquid liquid microextraction (ZnO-NF VA-LLME) was developed and employed in extraction of inorganic mercury (Hg(2+)) in environmental water samples, followed by cold vapor atomic fluorescence spectrometry (CV-AFS). Unlike other dispersive liquid liquid microextraction techniques, ZnO-NF VA-LLME is free of volatile organic solvents and dispersive solvent consumption. Analytical signals were obtained without back-extraction from the ZnO-NF phase prior to CV-AFS determination.