Simple and large-scale synthesis of β-phase molybdenum carbides as highly stable catalysts for dry reforming of methane

In this work, we propose a facile, fast and large-scale synthesis of β-Mo 2 C catalysts (about 100 grams). The current approach uses a simple solid mixture of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O and carbon nanotubes (CNTs) as a precursor and employs a fast heating rate method without holding time. Moreover, there was no need for passivating the carbide products. A series of β-Mo 2 C/CNT catalysts (denoted as MoC-5, -15, -30 and -60) were successfully prepared from the precursors with the Mo content ranging from 5 to 60 wt% and their catalytic activities for dry reforming of methane (DRM) were evaluated. CH 4 -TPSR and CO 2 -TPO over the fresh samples proved that the abilities of CH 4 dissociation and oxidation resistance of β-Mo 2 C were greatly enhanced by compositing with CNTs. It was also found that these abilities were dependent on the Mo content, the particle size and the interaction between β-Mo 2 C and CNTs. Among these β-Mo 2 C/CNT catalysts, MoC-30 showed the best catalytic stability for DRM, attributed to its high activity for CH 4 dissociation and high resistance to oxidation. Additionally, it is worth noting that the catalytic stability of monometallic MoC-30 was found to be superior to that of bimetallic Ni/β-Mo 2 C (recently known to be an efficient non-noble metal catalyst for DRM). The catalytic stability of monometallic β-Mo 2 C/CNTs was found to be superior to that of bimetallic Ni/β-Mo 2 C under similar reaction conditions.