Highly sensitive acetone sensor based on WO3 nanosheets derived from WS2 nanoparticles with inorganic fullerene-like structures

Metal oxide semiconductor (MOS) gas sensors are promising for applications in environmental monitoring, dangerous gas detection, and disease diagnosis. Seeking for advanced MOS sensing materials that possess high sensitivity and low limit of detection (LOD) at sub-ppm level is a great challenge. Here, we report the first creation of two-dimensional (2D) WO3 nanosheets by annealing of the inorganic fullerene (IF)-like WS2 nanoparticles that were prepared via sulfurization of WO3 nanoparticles. Transformation of WS2 to WO3 was realised during the annealing process, simultaneously accompanied by the collapse of the hollow IF-WS2 structures and the formation of tiny 2D WO3 nanosheets with a lateral size of 40-80 nm. The resulting 2D WO3 nanosheets exhibited highly enhanced acetone-sensing performance in terms of sensitivity, selectivity, and response/recovery rates compared with the WO3 nanoparticles used as precursor for the synthesis of the IF-WS2 nanoparticles. The nanosheets also demonstrated great repeatability, reliable long-term stability, and very low LOD, making them a promising candidate as gas sensor to detect breath acetone.