Directly transforming SnS2 nanosheets to hierarchical SnO2 nanotubes: Towards sensitive and selective sensing of acetone at relatively low operating temperatures

SnO2-based materials are helpful to detect low concentration of volatile organic compounds (VOCs), whereas high operating temperatures (>= 350 degrees C), poor selectivity and inadequate detection limit of the pristine SnO2 hinder their broader applications. An alternative strategy to address these challenge issues is to adopt porous SnO2 nanotubes (NTs) constructed with ultrathin walls to monitor VOCs. However, inconvenient synthetic routes and low-yield rate of NTs with satisfactory wall thickness restrained the application of SnO2 NTs. Herein, we directly turned SnS2 nanosheets to the porous SnO2 NTs by thermal oxidizing the SnS2 precursor in air. After thermal treatment, high crystallinity and porous hierarchical SnO2 NTs with ultrathin walls were successfully synthesized without any impurities. After decorated with Au nanoparticles (NPs), a strong interaction between the Au NPs and hierarchical SnO2 NTs was witnessed. Compared with those reported SnO2-based materials, hierarchical SnO2 NTs indeed improved the gas sensing properties; particularly, the sensor using Au-SnO2 NTs composite gave the largest sensing magnitude, satisfactory detection limit and high selectivity to acetone at operating temperature of 200 degrees C. Conclusively, the innovation of transforming SnS2 to the hierarchical SnO2 NTs paves the way to building SnO2 NTs from 2 dimensions ultrathin bricks, and for high performance sensing VOCs.