Two-dimensional molybdenum disulfide nanoparticles intercalated between graphite layers: TEM observation and desulfurization behaviour.

Two-dimensional molybdenum disulfide nanoparticles were formed in graphite interlayers by sulfurization and reduction-sulfurization treatments of a molybdenum chloride-intercalated graphite compound (MoCl5-GIC). When MoCl5-GIC was treated at 623 or 823 K under a flowing mixed gas of hydrogen sulfide and hydrogen, molybdenum disulfide nanosheets (MoS2-GIC(i)) with a thickness of 1-2 layers and lateral dimensions extending over several hundred nanometers were obtained. In contrast, when MoCl5-GIC was first reduced at 873 K under a hydrogen flow and subsequently sulfurized at 823 K under a mixed gas of hydrogen sulfide and hydrogen, molybdenum disulfide clusters (MoS2-GIC(ii)) with lateral dimensions of several tens of nanometers and consisting of 4-5 stacked layers were formed in the graphite interlayers. MoS2-GIC(i) and MoS2-GIC(ii) exhibited comparable catalytic activities for the hydrogenation of naphthalene; however, in the hydrodesulfurization of dibenzothiophene, MoS2-GIC(ii) showed higher desulfurization selectivity.