UV light irradiation enhanced gas sensor selectivity of NO₂ and SO₂ using rGO functionalized with hollow SnO₂ nanofibers

Herein, to enhance selective detection of NO₂ and SO₂ using a single device, an ultraviolet (UV) light activated gas sensor has been reported based on reduced graphene oxide (rGO) functionalized with hollow SnO₂ nanofibers (NFs) at room temperature. The porous hollow SnO₂ NFs are synthesized using electrospinning and calcination treatment, then different contents of SnO₂ are introduced to rGO for preparation of rGO/SnO₂ nanocomposites by facile magnetic stirring and ultrasonic treatment. The rGO/SnO₂ samples reveal obvious sensing response, great reversibility and good humidity resistance to target gases at ppm level. Under different intensities of UV light illumination, gas sensing properties of rGO/SnO₂ are studied to explore the photoexcited sensing behaviors. The greatly enhanced selective detection to NO₂ (102%) and SO₂ (11%) is achieved with a response ratio of 9.3 by using UV light illumination. The results show sensor response and selectivity can be improved using appropriate intensity of excitation light, demonstrating significant modulation effect of UV light assistance on gas detection. The mechanism may be attributed to light motivated electron-hole pairs due to built-in electric fields under UV light illumination, which can be captured by target gases and lead to UV controlled gas sensing performance.