Synthesis of straight multi-walled carbon nanotubes by arc discharge in air and their field emission properties

Abstract

The possibility of preparing straight multiwalled carbon nanotubes (MWCNTs) on a large scale is demonstrated using direct current arc discharge with a rotating graphite anode in low pressure air. The process is time-saving, economical, and non-hazardous. It is found that the optimum air pressure for the highest yield of MWCNTs is about 60 Torr. Investigation of the internal organization of the cathode deposit reveals that many columns about 40 lm in diameter are closely packed and mechanically stable. The highest content of MWCNTs is found in the intercolumnar spaces between columns. Emitters made of the cathode deposits that contain a large number of straight nanotubes exhibit outstanding field emission properties. The turn-on electric field decreases from 1.44 to 0.93 V/lm and the field enhancement factor b increases from about 3,190 to 7,830 only after simple burning at 750°C for 30 min in air. The results indicate that MWCNTs prepared by arc discharge in air are promising for field emission application.

Carbon nanomaterials synthesized by arc discharge hot plasma

“…However, the high air pressure in the arc chamber easily results in a unstable plasma in the arc discharge process due to the violent reaction between excessive O 2 and graphite electrode. Zhao et al [54] investigated systematically the synthesis of MWCNTs using DC arc discharge with a rotating graphite anode in low-pressure air. It is found that the optimum air pressure for the highest yield of MWCNTs is about 60 Torr.…”

Free-binder lithium ion battery based on a hybrid multiwalled carbon nanotube-graphitic platelet architecture

“…The hybrid architecture materials of MWCNTs and graphitic platelets were prepared in a sealed chamber using DC arc discharge method following the process described in our previous work [9,10]. The cylindrical deposit was firstly cut into a slice with a thickness of~1 mm as anode material and then simply heated at 750°C for 30 min in air.…”

Electron gun using coniferous carbon nano-structure

“…The field enhancement factor of CCNSs is 27000, calculated from the slope of the F-N plot by assuming the work function of CNTs as 5.0 eV [12]. Some groups have reported previously the field enhancement factors of CNT-based emitters such as a self-standing CNT fiber [21], vertically aligned CNT arrays on graphene layers [22], few-layer graphene on CNTs [23], and straight multi-walled CNTs [24] as 65000, 5340, 3980, and 7830, respectively. On the comparison of CCNS and other CNT-based emitters, the value for CCNS is between that of a CNT fiber and graphene.…”