Selective detection of chlorine at room temperature utilizing single-walled carbon nanotubes functionalized with platinum nanoparticles synthesized via ultraviolet irradiation

In this study, photoreduction by an ultraviolet (UV) irradiation method was applied to synthesizing platinum (Pt) nanoparticles into networked single-walled carbon nanotubes (SWCNTs). To investigate the growth behaviour of Pt nanoparticles, we systematically controlled the UV irradiation intensity and exposure time. These processing factors significantly influenced the formation behaviour of Pt nanoparticles regarding diameter and density. Utilizing the photoreduction process, the sidewalls of SWCNTs were uniformly functionalized with Pt nanoparticles synthesized under optimal UV conditions. For application as practical chlorine (Cl2) sensors, the sensing performances of Pt nanoparticle-functionalized SWCNTs for Cl2 were compared against the injection of other gases such as nitrogen dioxide, ammonia and carbon monoxide. The results indicate that UV irradiation is an effective way to functionalize the sidewalls of SWCNTs with catalytic Pt nanoparticles. In addition, the Cl2 selectivity and response of SWCNT-based gas sensors were enhanced by functionalization with catalytic Pt nanoparticles.