Enhanced room temperature selective ammonia sensing based on SnO2 decorated MXene

Abstract

SnO₂/MXene nanocomposites were prepared by decorating SnO₂ nanoparticles over few layer MXene using ultra-sonication.  The SnO₂/MXene composite exhibit highly selective and sensitive towards trace level ammonia detection at room temperature. The linear sensing response R²=0.938 and R²=0.971 obtained for ammonia concentration 0.5 to 5 ppm and 10 to 100 ppm respectively.  The SnO₂ nanoparticles loaded MXene sheets shows shorter response time about 16 sec compared with pristine SnO₂ response time (~61 sec). The formation of Schottky junction between SnO2 and MXene results in the formation the charge depletion between the SnO2/MXene interface and further the charge depletion increases over ammonia vapor interaction resulting in the increase of the sensor resistance. Besides, quick reversibility over 50 cycles, room temperature operation, high sensitivity, faster response/recovery time, and simple fabrication approach of making SnO₂ loaded MXene materials could be interesting for making next generation selective detection of ammonia molecules.