Study on reduction reaction of MoO₂ powder with NH₃

Abstract

Reaction mechanism between MoO 2 powder and NH 3 in the temperature range of 1028-1273 K has been investigated. The results show that reduction products are strongly dependent on the reaction temperature employed. It is found that molybdenum nitride (Mo 2 N) can be successfully synthesized when the temperature is below 1078 K, with the morphologies keep the same as that of the raw material MoO 2 . Although the temperature is above 1078 K, metal Mo powder will be turned up; at the even higher temperatures, the thermodynamically stable phase will be metal Mo. In addition, MoO x N 1Àx as an intermediate product is formed during the reduction processes.

Synthesis of molybdenum nitrides nanosheets by nitriding 2H‐MoS2 with ammonia

“…In order to measure the weight change continuously in the reaction process, a thermal analysis system (HTC‐2; Beijing Hengju Instrument Ltd., Beijing), which included a thermo‐gravimetry (TG) microbalance with a precision of ±0.1 μg, was used. The corresponding schematic diagram was described elsewhere . A nonisothermal thermo‐gravimetry experiment was carried out firstly to establish the temperatures for isothermal experiments.…”

“…The corresponding schematic diagram was described elsewhere. 18 A nonisothermal thermo-gravimetry experiment was carried out firstly to establish the temperatures for isothermal experiments. During the nonisothermal experimental process, about 80 mg MoS 2 samples were used and placed into an alumina crucible which was then placed into the furnace.…”

“…The method of preparing metal nitrides nanosheets published to date is limited to exfoliation of layered materials and gas‐phase synthesis . Heat treatment of metal oxides in ammonia has been used frequently to either N‐dope them or transform oxides to 3D nitrides . Until recently, 2D MoN and V 2 N were prepared via salt‐templated synthesis with 2D metal oxide precursors in ammonia .…”

“…16 Heat treatment of metal oxides in ammonia has been used frequently to either N-dope them or transform oxides to 3D nitrides. [16][17][18] Until recently, 2D MoN and V 2 N were prepared via salttemplated synthesis with 2D metal oxide precursors in ammonia. 5 Besides, ammoniation of other 2D precursors such as GaSe 2 and transition metal carbides (MXenes) to yield the 2D metal nitride GaN, MoN, and V 2 N have also been reported recently.…”

A low‐cost and efficient pathway for preparation of 2D MoN nanosheets via Na2CO3‐assisted nitridation of MoS2 with NH3

“…However, when the temperature was 850°C, as shown in Figure A, some Mo 2 C appeared in the final product. It has been known that molybdenum nitride is unstable and tends to decompose when the temperature is above 820°C . Therefore, at 850°C, Mo 2 C could be more stable than MoN, and Mo 2 C could not be nitridized to Mo 2 N, but MoN could be carbonized to Mo 2 C.…”