UV Illumination-Enhanced Molecular Ammonia Detection Based On a Ternary-Reduced Graphene Oxide–Titanium Dioxide–Au Composite Film at Room Temperature

In this work, we report on UV illumination-enhanced room-temperature trace NH3 detection based on ternary composites of reduced graphene oxide nanosheets (rGO), titanium dioxide nanoparticles (TiO2), and Au nanoparticles as the sensing layer, which is the first reported so far. The effect of the UV state as well as componential combination and content on the sensing behavior disclosed that rGO nanosheets served not only as a template to attach TiO2 and Au but also as an effective electron collector and transporter, TiO2 nanoparticles acted as a dual UV and NH3 sensitive material, and Au nanoparticles could increase the sorption sites and promote charge separation of photoinduced electron–hole pairs. The as-prepared rGO/TiO2/Au sensors were endowed with a sensing response of 8.9% toward 2 ppm of NH3, a sensitivity of 1.43 × 10–2/ppm within the investigated range, nice selectivity, robust operation repeatability, and stability, which was fairly competitive in comparison with previous work. Meanwhile, the experimental results provided clear evidence of inspiring UV-enhanced gas detection catering for the future demand of low power-consumption and high sensitivity.