Remarkably accelerated room-temperature hydrogen sensing of MoO^sub 3^ nanoribbon/graphene composites by suppressing the nanojunction effects

Low-dimensional oxide semiconductor has stimulated the development of hydrogen sensors due to its fast and sensitive hydrogen response at room temperature. Intense interests always reside in the enhancement of hydrogen sensing performance by suppressing the negative impact of the interfaces and junctions on the sensing properties. In this work, MoO3 nanoribbon/graphene composites were synthesized via a one-step hydrothermal route. The orthorhombic MoO3 nanoribbons, grown along the [001] orientation, were uniformly distributed in the graphene sheet networks. The composite system additionally provided large numbers of MoO3/graphene interfaces besides the homojunctions between the MoO3 nanoribbons, which opened up efficient electron transport paths, reduced the interface electron scattering and hence dramatically decreased the resistance of the system. The addition of graphene in the MoO3 nanoribbon/graphene composite brought great improvement on sensor response, response speed and recovery speed of the sensors at room temperature. The response and recovery times were respectively decreased to ∼10 s and ∼30 s by compositing MoO3 nanoribbons with graphene of 1.5 wt%. The performance enhancement could be attributed to the suppression of nanojunctions’ effect, increase of specific surface area and improvement of electron transportation in the MoO3 nanoribbon/graphene system.