Superior, rapid and reversible sensing activity of graphene-SnO hybrid film for low concentration of ammonia at room temperature

Abstract

A room temperature reversible ammonia (NH3) gas sensor based on resistive transduction mechanism was fabricated using SnO coated graphene film. This hybrid material was prepared by heating few layer graphene in air followed by heating in aqueous solution of SnCl2. The graphene-SnO hybrid demonstrated excellent and persistent sensing towards the low concentration of ammonia in air. The sensor showed response and recovery time 10% and 21% for 20ppm and 50ppm of NH3. No heating was required either for sensing or recovery. Reversible charge transfer between NH3 and Sn connected to graphene through oxygen, and high electrical conductivity of graphene are proposed to be responsible for high sensitivity of the hybrid film towards ammonia gas. The hybrid material showed >8months stability and sensing ability.