Synthesis of Numerous Edge Sites in MoS 2 via SiO 2 Nanorods Platform for Highly Sensitive Gas Sensor

The utilization of edge sites in two-dimensional materials including transition-metal dichalcogenides (TMDs) is an effective strategy to realize high-performance gas sensors because of their high catalytic activity. Herein, we demonstrate a facile strategy to synthesize the numerous edge sites of vertically aligned MoS 2 and larger surface area via SiO 2 nanorod (NRs) platforms for highly sensitive NO 2 gas sensor. The SiO 2 NRs encapsulated by MoS 2 film with numerous edge sites and partially vertical-aligned regions synthesized using simple thermolysis process of [(NH 4 ) 2 MoS 4 ]. Especially, the vertically aligned MoS 2 prepared on 500 nm thick SiO 2 NRs (500MoS 2 ) shows approximately 90 times higher gas-sensing response to 50 ppm NO 2 at room temperature than the MoS 2 film prepared on flat SiO 2, and the theoretical detection limit is as low as ∼2.3 ppb. Additionally, it shows reliable operation with reversible response to NO 2 gas without degradation at an operating temperature of 100 °C. The use of the proposed facile approach to synthesize vertically aligned TMDs using nanostructured platform can be extended for various TMD-based devices including sensors, water splitting catalysts, and batteries.