Synthesis and characterization of Au-attached single-walled carbon nanotube bundles

Efficient CO2 Electroreduction via Au-Complex Derived Carbon Nanotube Supported Au Nanoclusters

The production of value-added chemicals from CO₂ electroreduction, using renewable energy, provides an appealing route to achieve the goal of carbon neutrality. Challenges remain in designing and understanding of high-performance catalysts with restructuring behavior under electrochemical conditions. Here, the intrinsic performance enhancement of an Au-complex derived carbon nanotube-supported Au nanoclusters catalyst was demonstrated for CO₂ reduction. This catalyst exhibited impressive activity for yielding CO in both H-cell and flow cell reactors. Experimental results revealed that the synthesis procedure via metal complex reconstructing on proper support induced charge transfer between Au nanoclusters and carbon nanotubes, forming a rather electron-rich state for Au active sites, which greatly contributed to the CO₂ activation pathway.

Origin of enhancement in Raman scattering from Ag-dressed carbon-nanotube antennas: experiment and modelling

The D- and G-band Raman signals from random arrays of vertically aligned, multi-walled carbon nanotubes are significantly enhanced (up to ∼14×) while the signal from the underlying Si substrate is simultaneously attenuated (up to ∼6×) when the nanotubes are dressed, either capped or coated, with Ag. These Ag-induced counter-changes originate with the difference in geometry of the nanotubes and planar Si substrate and contrast in the Ag depositions on the substrate (essentially thin film) and the nanotube (nano-particulate). The surface integral equation technique is used to perform detailed modelling of the electromagnetic response of the system in a computationally efficient manner. Within the modelling the overall antenna response of the Ag-dressed nanotubes is shown to underpin the main contribution to enhancement of the nanotube Raman signal with hot-spots between the Ag nanoparticles making a subsidiary contribution on account of their relatively weak penetration into the nanotube walls. Although additional hot-spot activity likely accounts for a shortfall in modelling relative to experiment it is nonetheless the case that the significant antenna-driven enhancement stands in marked contrast to the hot-spot dominated enhancement of the Raman spectra from molecules adsorbed on the same Ag-dressed structures. The Ag-dressing procedure for amplifying the nanotube Raman output not only allows for ready characterisation of individual nanotubes, but also evidences a small peak at ∼1150 cm^-1 (not visible for the bare, undressed nanotube) which is suggested to be due to the presence of trans-polyacetylene in the structures.

Controllable gold nanoparticle deposition on carbon nanotubes and their application in immunosensing

A CNT–AuNPs hybrid nanocomposite platform was prepared from nanodisperse AuNPs in N-[3-(trimethoxysilyl)propyl]ethylenediamine (EDAS) sol–gel matrices with purified MWCNT.

Sensitive Detection of Elemental Mercury Vapor by Gold Nanoparticle Decorated Carbon Nanotube Sensors

Low-cost, low power consumption gas sensors that can detect or quantify various gas analytes are of increasing interest for various applications ranging from mobile health, to environmental exposure assessment and homeland security. In particular miniature gas sensors based on nanomaterials that can be manufactured in the form of sensor arrays present great potential for the development of portable monitoring devices. In this study, we demonstrate that a chemiresistive nanosensor comprised of single walled carbon nanotubes decorated with gold nanoparticles has impressive sensitivity to elemental mercury (Hg) gas concentrations, with a lower detection limit as low as 2 ppb(v). Furthermore, this nanosensor was found to regenerate, though slowly, without any additional recovery steps. Finally, the mercury vapor sensing mechanism allowed for direct investigations into the origin of Surface Enhanced Raman Scattering (SERS) in carbon nanotubes decorated with Au nanoparticles.