Template-Assisted Controllable Synthesis of Uniform Plate-Like Crystalline Tungsten Trioxide and Its Excellent H2S Gas-Sensing Properties

Nanostructured cubic crystalline tungsten trioxide (WO3) with uniform plate-like morphology was duplicated in a solution phase by using a monodispersed hexagonal lamelliform aminefunctionalized SBA-15 as a template. It was found that the templates play two significant roles in uniform distribution of ion-exchanged metal precursors in the monolayer of positively-charged amine groups on the pore surface of SBA-15, and effectively confine the size and shape of the guest nano-materials WO3. X-ray diffraction, nitrogen adsorption/desorption, Fourier transformation infrared spectroscopy, solid state NMR spectrometry, transmission electron microscopy and field emission scanning electron microscopy were employed to characterize the products. The as-prepared crystalline WO3 with optimal morphology showed excellent gas sensing properties upon exposure to H2S gas in practical application. Herein, we developed an excellent H2S sensor with high sensitivity, good selectivity, short response/recovery time and high reproducibility, and presented a novel strategy to template synthesize crystalline WO3 nanostructures with defined plate-like morphology.