Selective preparation of polyhedral graphite particles and multi-wall carbon nanotubes by a transferred arc under atmospheric pressure

► PGP was prepared at high arc current and large anode diameter; MWNT was prepared at low arc current small anode diameter. ► PGP was prepared at high arc current and large anode diameter; MWNT was prepared at low arc current small anode diameter. ► Relatively high ratio of carbon ions to carbon radicals contributes to the formation of PGP. ► Relatively low ratio of carbon ions to carbon radicals leads to the formation of MWNT.