A novel synthesis of graphene quantum dots via thermal treatment of crude graphite oxide in a dry and alkaline condition, and their application in uranyl detection.

In this article, a novel method to synthesize graphene quantum dots was developed via thermal treatment of crude graphite oxide (GO) in a dry and alkaline condition to cut the crude GO sheets into small graphene quantum dots (named as aGQDs). The aGQDs are nano-scale reduced graphene oxide pieces with the sizes around 5-10 nm. The aGQDs could disperse in water for their richment of oxygen-containing groups.

Graphene quantum dot electrochemiluminescence increase by bio-generated HO and its application in direct biosensing.

In this study, a novel signal-increase electrochemiluminescence (ECL) biosensor has been developed for the detection of glucose based on graphene quantum dot/glucose oxidase (GQD/GO) on Ti foil. The proposed GQD with excellent ECL ability is synthesized through a green one-step strategy by the electrochemical reduction of graphene oxide quantum dot. Upon the addition of glucose, GO can catalytically oxidize glucose and the direct electron transfer between the redox centre of GO and the modified electrode also has been realized, which results in the bio-generated HO for ECL signal increase in GQD and realizes the direct ECL detection of glucose.

Flexible and adhesive tape decorated with silver nanorods for in-situ analysis of pesticides residues and colorants.

A flexible adhesive tape decorated with SERS-active silver nanorods (AgNRs) in the form of an array nanostructure is described. The tape was constructed by transferring the AgNRs nanostructures from silicon to the transparent tape by a "paste & peel off" procedure. The transparent, sticky, and flexible properties of commercial tapes allow almost any SERS-inactive irregular surface to be detected in-situ by pasting the SERS tape onto the position to be analyzed.

The contribution of photoinduced charge-transfer enhancement to the SERS of uranyl(VI) in a uranyl-AgO complex.

Charge-transfer (CT) is an important enhancement mechanism in the field of surface-enhanced Raman scattering (SERS) that typically increases the Raman intensity of molecules by as much as 10-100 times. Herein, a low-cost AgO aggregates substrate was prepared via a facile chemical precipitation method, and the calculated CT-based enhancement factor of the uranyl ions adsorbed on it reached as high as 10, a metal-comparable value. The efficient photoinduced CT process from the valence band of AgO to the LUMO of uranyl ions under appropriate excitation sources resulted in the repulsion of the axial oxygen atoms of the OUO bond, which enhanced its polarizability, creating a more intense Raman mode.

Assembly of porphyrin-based uranium organic frameworks with (3,4)-connected pto and tbo topologies.

Three (3,4)-connected uranyl-organic frameworks (UOFs) with pto and tbo topologies were synthesized. The UOF with a pto net possesses a 2-fold interpenetrating network and exhibits 2D interconnected channels. The UOF with a tbo net is constructed from two types of ultralarge nanocages.

Advances in the use of carbonaceous materials for the electrochemical determination of persistent organic pollutants. A review.

Persistent organic pollutants (POPs) are key pollutants due to their persistence, refractory biodegradation, high toxicity and bioaccumulation in the food chain. This review (with 93 refs.) covers the progress made in the past decades in the application of carbonaceous materials for electrochemical detection of POPs as listed in the Stockholm Convention.

Self-assembly of silver nanoparticles as high active surface-enhanced Raman scattering substrate for rapid and trace analysis of uranyl(VI) ions.

A facile surface-enhanced Raman scattering (SERS) substrate based on the self-assembly of silver nanoparticles on the modified silicon wafer was obtained, and for the first time, an advanced SERS analysis method basing on this as-prepared substrate was established for high sensitive and rapid detection of uranyl ions. Due to the weakened bond strength of OUO resulting from two kinds of adsorption of uranyl species ("strong" and "weak" adsorption) on the substrate, the ν symmetric stretch vibration frequency of OUO shifted from 871cm (normal Raman) to 720cm and 826cm (SERS) along with significant Raman enhancement. Effects of the hydrolysis of uranyl ions on SERS were also investigated, and the SERS band at ~826cm was first used to approximately define the constitution of uranyl species at trace quantity level.

Graphene oxide amplified electrochemiluminescence of graphitic carbon nitride and its application in ultrasensitive sensing for Cu(2+).

Here for the first time, we present a novel electrochemiluminescence (ECL) sensor based on graphitic carbon nitride/graphene oxide (g-C3N4/GO) hybrid for the ultrasensitive detection of Cu(2+), which is a common pollutant in environmental system. The g-C3N4/GO shows stable ECL signal in the presence of the self-produced coreactant from oxygen reduction, and the ECL signal could be effectively quenched by Cu(2+), the possible ECL detection mechanism has been proposed in detail. GO can not only significantly enhance the cathodic ECL signal of g-C3N4 (∼3.