Are Non-Six-Membered Ring Defects Formed in Single-Walled Carbon Nanotubes Treated by a Fluorination-Defluorination Process?

Single-walled carbon nanotubes (SWCNTs) modified by introducing non-six-membered ring defects, such as five- and seven-membered rings, have attracted considerable attention because their conductivity is enhanced by increasing the electronic density of states at the Fermi energy level. However, no preparation method exists to efficiently introduce non-six-membered ring defects into SWCNTs. Herein, we attempt to introduce non-six-membered ring defects into SWCNTs by defect rearrangement of the nanotube framework using a fluorination-defluorination process.

Controlled introduction of defects into single-walled carbon nanotubes via a fluorination-defluorination strategy using xenon difluoride and their alkaline oxygen reduction reaction catalytic activity.

The defect edges in carbon nanomaterials have attracted attention as catalytic active sites for the oxygen reduction reaction (ORR) of the cathode in electrolyte fuel cells, and the defect control in carbon nanomaterials is becoming increasingly important. This study evaluates a fluorination-defluorination strategy for the controlled introduction of defects into single-walled carbon nanotubes (SWCNTs) involving the fluorination of SWCNTs using xenon difluoride (XeF) and their subsequent defluorination through thermal annealing. We synthesized fluorinated SWCNTs with different fluorine contents using gaseous XeF and annealed the fluorinated SWCNTs at 1000 °C for 3 h under nitrogen gas flow.

Isolation and characterization of cbbL and cbbS genes encoding form I ribulose-1,5-bisphosphate carboxylase/oxygenase large and small subunits in Nitrosomonas sp. strain ENI-11.

The cbbL and cbbS genes encoding form I ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) large and small subunits in the ammonia-oxidizing bacterium Nitrosomonas sp. strain ENI-11 were cloned and sequenced. The deduced gene products, CbbL and CbbS, had 93 and 87% identity with Thiobacillus intermedius CbbL and Nitrobacter winogradskyi CbbS, respectively.