Exploring the Confinement Effect of Carbon Nanotubes on the Electrochemical Properties of Prussian Blue Nanoparticles.

A novel and efficient photochemical method has been proposed for the encapsulation of Prussian blue nanoparticles (PBNPs) inside the channels of carbon nanotubes (PB-in-CNTs) in an acidic ferrocyanide solution under UV/vis illumination, and the confinement effect of CNTs on the electrochemical properties of PBNPs is systematically explored. PB-in-CNTs show a faster electron-transfer process, an enhanced electrocatalytic activity toward the reduction of H2O2, and an increased anti-base ability compared to PBNPs loaded outside of CNTs (PB-out-CNTs). In addition, PB-in-CNTs show an increased electrochemical reversibility and an unexpected diameter-independent catalytic activity with the decrease of CNT diameters. The improved electrochemical properties of PB-in-CNTs are attributed to the modified electronic properties and dimensions of PBNPs induced by the confinement effect of CNTs. This work provides further insights into the confinement effect on the properties of nanomaterials and will inspire extensive relevant investigations in the development of novel composites or excellent catalysts.

Label-free strategy for in-situ analysis of protein binding interaction based on attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS).

A versatile ATR-SEIRAS methodology is described herein for highly sensitive analysis of immunoglobulin (IgG) recognition. This strategy allows in situ tracking of specific protein binding at the liquid-solid interface. Most importantly, interferential signal from environmental molecules (e.g., water, nonspecific binding molecules, and bulk molecules) can be eliminated to negligible levels by using the ATR analysis mode, and the sensitive IR structural information of target proteins is obtained simultaneously. A simplified numerical model has been established to quantitatively describe the kinetics and thermodynamics of protein recognition processes at surfaces. Compared with conventional label-free methods for protein binding study, experimental results obtained from IR spectroscopic information are more reliable. The presented ATR-SEIRAS method is powerful in studying surface limited protein binding reactions.

Determination of explosives using electrochemically reduced graphene.

A graphene-based electrochemical sensing platform for sensitive determination of explosive nitroaromatic compounds (NACs) was constructed by means of electrochemical reduction of graphene oxide (GO) on a glassy carbon electrode (GCE). The electrochemically reduced graphene (ER-GO) adhered strongly onto the GCE surface with a wrinkled morphology that showed a large active surface area. 2,4-Dinitrotoluene (2,4-DNT), as a model analyte, was detected by using stripping voltammetry, which gave a low detection limit of 42 nmol L(-1) (signal-to-noise ratio=3) and a wide linear range from 5.49×10(-7) to 1.1×10(-5) M. Further characterizations by electrochemistry, IR, and Raman spectra confirmed that the greatly improved electrochemical reduction signal of DNT on the ER-GO-modified GC electrode could be ascribed to the excellent electrocatalytic activity and high surface-area-to-volume ratio of graphene, and the strong π-π stacking interactions between 2,4-DNT and the graphene surface. Other explosive nitroaromatic compounds including 1,3-dinitrobenzene (1,3-DNB), 2,4,6-trinitrotoluene (TNT), and 1,3,5-trinitrobenzene (TNB) could also be detected on the ER-GO-modified GC electrode at the nM level. Experimental results showed that electrochemical reduction of GO on the GC electrode was a fast, simple, and controllable method for the construction of a graphene-modified electrode for sensing NACs and other sensing applications.