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

Abstract

In this paper, an efficient and low‐cost method was developed for producing isolated 2D MoN nanosheets via Na2CO3‐assisted nitridation and exfoliation of natural 2H‐MoS2 by NH3 at 700‐800°C. It was found that, in the presence of Na2CO3, the nitridation of MoS2 with NH3 was a topochemical transformation. After heat treatment the mixture of MoS2 and Na2CO3 in NH3 at 700‐800°C, layered MoN with intercalated Na2S was obtained. Na2CO3 can dramatically promote the topochemical nitridation and exfoliation of MoS2 in NH3. At 750°C, the time for complete nitridation of (commercial) MoS2 can be shortened to 2 hours, which is much shorter than 40 hours in the case without the addition of Na2CO3 as reported in the previous literature. After acid‐washing, the intercalated Na2S was removed, and the generated H2S promoted the further separation of the MoN nanosheets. Finally, dispersed high crystalline 2D MoN nanosheets with thickness of a few nanometers were successfully produced. This method may be also applicable for the production of other 2D nitrides or carbides by nitridation or carbonization of various transition metal dichalcogenides (TMDs) with the assistance of sulfur‐fixed agent.

Study on the reduction of commercial MoO3 with carbon black to prepare MoO2 and Mo2C nanoparticles

“…It was reported that this phenomenon also appeared in the reduction of MoO 2 with H 2 , CO, or NH 3 , which was called as topochemical/pseudomorphic transformation . The topochemical transformation was defined as adding, extracting or substituting elements to or from precursors for synthesis of new materials that retain the structure or, at least, morphology of precursors . Therefore, due to the poor migration ability of MoO 2 , the large MoO 2 particles were topochemically transformed to Mo 2 C. Based on the above analyses, the schematic diagrams of the reduction of commercial MoO 3 with carbon black and other different carbon sources were draw and shown in Figure .…”

Conformal Lithium Peroxide Growth Kinetically Driven by MoS2/MoN Heterostructures Towards High‐Performance Li−O2 Batteries

“…It is worth noting that the N 1s signal at 397.78 eV from MoÀ N bonding is overlapped with three other Mo 3p 3/2 peaks, designated to MoÀ N, MoÀ S and MoÀ O at 394.9, 395.79 and 399.44 eV, respectively. [36] Lastly, the spectrum of S 2p only points to one S 2À state, with its 2p 3/2 and 2p 1/2 spin orbitals located at 162.62 and 163.83 eV, respectively (Figure 2d). [29] Collectively, all the above microscopic and spectroscopic characterizations unequivocally attest to the successful fabrication of MoS 2 /MoN heterostructures on carbon cloth through the partial nitridation of MoS 2 .…”

“…Figure 2(c) displays the high resolution N 1s spectrum. It is worth noting that the N 1s signal at 397.78 eV from Mo−N bonding is overlapped with three other Mo 3p 3/2 peaks, designated to Mo−N, Mo−S and Mo−O at 394.9, 395.79 and 399.44 eV, respectively [36] . Lastly, the spectrum of S 2p only points to one S 2− state, with its 2p 3/2 and 2p 1/2 spin orbitals located at 162.62 and 163.83 eV, respectively (Figure 2d) [29] .…”

Utility of NaMoO3F as a Precursor for Homogeneous Distribution of Cobalt Dopants in Molybdenum Oxynitrides

“…These reports imply that the phase, the crystallinity, and the Co/O dopant state in the MoN should be controlled simultaneously for further improvement of molybdenum nitride‐based ORR catalytic activity. Although nitridation of MoCl 5, [5c] MoS 2, [6] Cs 2 Mo 6 Br 14 , [7] Cs 2 Mo 6 Cl 14 [7] , and MoO 3 with NaCl [8] has been converted into hexagonal MoN phase, the synthetic process of MoN has been very limited until now. This limitation can dramatically suppress the simultaneous control.…”