In situ fabrication of a NiO nanoparticles/single-layered MXene nanosheet Schottky heterojunction toward sensing xylene and formaldehyde

Abstract

While air safety issues caused by indoor decoration have received extensive attention, real-time monitoring of toxic gases is still a severe technical challenge. Therefore, a xylene and formaldehyde dual gas sensor with easy operation and high stability is proposed in this study. Herein, a NiO–MXene heterostructure was constructed by recombining NiO nanoparticles with a two dimensional layered material Ti₃C₂T_x MXene by in situ precipitation. The results revealed that the NiO–MXene based sensors not only showed good responses to xylene at room temperature, but also showed 5.36 times higher response than that of the pure NiO based sensor to 100 ppm formaldehyde at 170 °C. It also showed good repeatability and long-term stability. The formation of a hybrid heterojunction by single-layered MXene nanosheets combined with a p-type semiconductor NiO is an essential factor for the enhanced gas sensing performance. This work is of significance for the preparation of dual or multiple gas sensors, and has an application potential in ensuring the safety of the indoor environment.