Preparation of industrial grade MoO₂ by the reaction between industrial grade MoO₃ and activated carbon

Abstract

In this study, the reaction between industrial grade molybdenum trioxide powders and activated carbon has been investigated in order to produce industrial grade molybdenum dioxide (MoO2). Effects of activation carbon addition and reaction temperature on the product compositions are both illustrated. Increasing the reaction temperature can significantly improve the reaction rate. It is difficult for them to react completely when the temperature is lower than 550 °C. However, industrial grade MoO2 powders can be obtained when the temperature is up to 650 °C. It is also found that there is no intermediate product Mo4O11 formed during the reaction process of MoO3 by activated carbon, which is different from the case of hydrogen reduction of MoO3 to MoO2. The crystalline size of the obtained MoO2 becomes very small relative to that of the raw material MoO3.

Toward Low-Temperature Solid-Source Synthesis of Monolayer MoS2

“…The reduction of MoO 3 into MoO 3– x is crucial for incoming S to react with volatile molybdenum (Mo) species in order to grow MoS 2 . It is important to note that at growth temperatures around 560 °C, MoO 3 reduction is near the limit of reaction with trace amounts of carbon present . Both the reduced system pressure of 490 Torr and the incoming volatile sulfur introduced at elevated temperatures promote the reduction of MoO 3 into volatile suboxide MoO 3– x .…”

“…In addition to the PTAS seed layer promoting initial MoS 2 nucleation from which grains grow, the trace amounts of carbon from the diffusing seed layer also act as a catalyst, promoting reduction of MoO 3 powder into volatile suboxide MoO 3−x . 47 The reduction of MoO 3 into MoO 3−x is crucial for incoming S to react with volatile molybdenum (Mo) species in order to grow MoS 2 . It is important to note that at growth temperatures around 560 °C, MoO 3 reduction is near the limit of reaction with trace amounts of carbon present.…”

“…It is important to note that at growth temperatures around 560 °C, MoO 3 reduction is near the limit of reaction with trace amounts of carbon present. 47 Both the reduced system pressure of 490 Torr and the incoming volatile sulfur introduced at elevated temperatures promote the reduction of MoO 3 into volatile suboxide MoO 3−x . 48 When sufficient volatile MoO 3−x is matched with an optimal flux of incoming sulfur atoms on the substrate surface, further reaction occurs to grow 1L MoS 2 films.…”