Hierarchical nanohybrids of B- and N-codoped graphene/mesoporous NiO nanodisks: an exciting new material for selective sensing of H2S at near ambient temperature

Hydrogen sulfide (H2S) is an extremely toxic gas and comes under the classification of chemical asphyxiants. To date, numerous metal oxide-based gas sensors have been developed for the detection and quantification of H2S. However, high sensing temperature, low sensitivity, humidity dependence, and very high response/recovery time severely limit their practical applications. Herein, we prepared hierarchical mesoporous nickel oxide (NiO) nanodisks and boron–nitrogen co-doped reduced graphene oxide (rGO)-NiO (NiOBNG) nanodisk composites for H2S sensing. The as-prepared materials were investigated by several techniques to determine their morphologies, crystal structures, phase purity, and compositions. The sensing response of the NiOBNG sensor to 100 ppm H2S at 150 °C was ∼82, and the detection limit of the sensor was ∼24 ppb. The NiOBNG sensor showed 2- and 3-fold stronger response compared to pristine rGO incorporated NiO and bare NiO nanodisk sensors. The enhanced sensing performance of the NiOBNG sensor is attributed to the presence of several catalytically active sites provided by boron and nitrogen doped rGO in the NiOBNG nanocomposite. The ease of the synthesis procedure, excellent sensitivity, selectivity, rapid response, high stability, and ambient temperature operation make for intriguing, promising practical applications of our NiOBNG sensor, especially in explosive environments and medical diagnosis.