rGO decorated NiO-BiVO4 heterojunction for detection of NO2 at low temperature

The combination of semiconductor heterojunction with rGO is recognized to be a promising method to improve the sensing performance of gas sensor. The 3.7 wt% rGO-NiO-BiVO4 composite was synthesized successfully by a simple hydrothermal and metal organic decomposition method. The gas-sensing tests reveal that the highest response of the ternary composite is 4 times and 8 times higher than the rGO-NiO junction and the pure NiO, respectively, towards 2 ppm NO2 at 60 degrees C, and the ternary composite exhibits rapid response. Moreover, the composite exhibits the highest response to NO2 among all tested gases, such as CO, toluene, ethanol, NH3 and formaldehyde, that is, the composite towards NO2 has excellent selectivity. The improvement is attributed to the effective electron transfer at interface of heterojunction and the increase of surface area and surface defect due to rGO loading. The work has reference value for improving gas sensing performance of p-type semiconductor.

Automated summary

The combination of semiconductor heterojunction with rGO has led to the successful synthesis of a ternary composite with high selectivity and rapid response to NO2. This improvement is attributed to effective electron transfer at the heterojunction interface and the increase in surface area and surface defects due to the introduction of rGO.