A novel carbothermal reduction nitridation route to MoN nanoparticles on CNTs support

Abstract

MoN nanoparticles in a size range around 50 nm were obtained on CNTs support via a novel carbothermal reduction nitridation (CRN). For the first time, a common (NH₄)₆Mo₇O₂₄·4H₂O can be used as a Mo source to prepare MoN nanoparticles. A Mo-containing precursor was in a first step carburized and was reduced to a MoO_xC_y/Mo mixture. During further carbothermal nitridation this mixture-phase was shifted to the MoN phase through either a Mo₂C or MoO_xN_y intermediate. Compared with the conventional NH₃-temperature-programmed treatment (TPT) route that produced Mo nitride from MoO₂ with rigorous heating method, the CRN route favored the formation of Mo nitride from easily nitridable MoO_xC_y/Mo, MoO_xN_y and Mo₂C intermediates. The phase structure of the Mo nitride product was greatly dependent on nitridation reaction pathway. The NH₃-TPT route yielded cubic Mo₂N, while the CRN process produced hexagonal MoN.