The synthesis of metal organic frameworks derived 3D porous V 2 O 5 microrods for NO 2 detection and its UV-enhanced sensing performance

As an n-type metal oxide semiconductor (MOS), vanadium pentoxide (V 2 O 5 ) has shown great potential in gas sensing, especially for the detection of NO 2. Herein, a highly sensitive NO 2 sensor based on 3D porous V 2 O 5 microrods (MRs) derived from metal organic frameworks (MOFs) was reported. The porous structure of vanadium-based MOF-derivatives (MIL-47) was tuned by the control of annealing temperature (300 °C–600 °C) in the pyrolysis process. The gas sensors with the MOF-derivatives are exposed to NO 2 at 150 ℃ for gas sensing tests. The sensor with MOF-derivatives annealed at 500 °C (MIL-47–500) showed the highest response (527 %) to 50 ppm NO 2. It also showed excellent selectivity, low limit of detection, and good repeatability. The NO 2 -sensing behaviors of the MIL-47–500 sensor under ultraviolet (UV) illumination have also been investigated. Under UV illumination, the response of the MIL-47–500 sensor increased to 706 %. At 75 °C, the response of the MIL-47–500 sensor toward 50 ppm NO 2 was significantly improved from 57 % to 538 % under UV illumination. The response/recovery times were reduced from 102 s/300–48 s/178 s. The excellent performance was attributed to the unique porous structure of MIL-47–500 and the UV light excited charge carriers.