Abstract
A surface engineering approach is exploited to enhance the performance of H 2 sensors consisting of a single-wall carbon nanotube film/graphene 3D electrode decorated with catalytic Pt nanoparticles using atomic layer deposition (Pt-NPs/SWCNTs/Gr). Specifically, C-band ultraviolet (UVC) radiation has been applied on the Pt-NPs/SWCNTs/Gr sensors for up to 20 minutes to activate the carbon surface and enhanced H 2 sensitivity and response speed have been obtained. Remarkably, at the optimal UVC irradiation of 10 minutes (intensity of 4.6 mW/cm 2 ), the H 2 gas response was enhanced by up to 4.3 fold, together with an enhanced response speed by 3.6 times as compared to that of the as-made Pt-NPs/SWCNTs/Gr sensors before the UVC irradiation. Specifically, a high H 2 response up to 32% has been achieved at 10% H 2 concentration. This enhancement can be attributed to desorption of residual molecules adsorbed on the SWCNTs and graphene surfaces during the sensor fabrication using UVC irradiation. This result illustrates the importance of the carbon surface activation in development of high-performance H 2 sensors using carbon nanostructures. The obtained high performance in the Pt-NPs/SWCNTs/Gr sensors can be attributed to the large sensing surface area of SWCNT films with carbon surface activated using UVC treatment, the catalytic benefit of the conformally coated Pt-NPs, and high mobility signal transport through graphene. In addition, this result demonstrates that the UVC irradiation can provide an effective, non-destructive, and facile method to activate the carbon surface on sensors composed of carbon nanostructures.