Production of vanadium-carbon clusters using dc arc discharges with pulsedhelium/methane gas injection

Experimental studies of the synthesis of new types of vanadium-carbon clust ers have been carried out using de are discharges, where a pair of graphite rods mixed with the vanadium carbide (VC) powders were used as the electro des. A high-pressure pulsed gas injection technique, where pulsed He gases were periodically injected into the de are plasma to cool the excited carbo n and vanadium atoms, was used. The effect of an addition of carbon atoms o n cluster production was also examined by injecting pulsed CH4 gases in add ition to high-pressure He gas pulses. The soots produced in the de are disc harges were analyzed using a laser desorption reflectron type time-of-fligh t (TOF) mass spectrometer. Experimental results show that when CH4 gas was added to He gas with a partial pressure of 15%, enhanced VnC2n clusters wit h a VC2-mass spacing of Deltam/z = 75 were detected in the mass range of 22 5 < m/z < 675. Experiments show that these vanadium-carbon clusters are for med by the vanadium atoms evaporated from the electrodes and the carbon ato ms supplied from the injected CH4 gas.