Porous CrO Architecture Assembled by Nano-Sized Cylinders/Ellipsoids for Enhanced Sensing to Trace HS Gas.

How to achieve high sensing of CrO-based sensors for harmful inorganic gases is still a challenge. To this end, CrO nanomaterials assembled from different building blocks were simply prepared by chromium salt immersion and air calcination with waste scallion roots as the biomass template. The hierarchical architecture calcined at 600 °C is constructed from nanocylinders and nanoellipsoids (named as CrO-600), and also possesses multistage pore distribution for target gas accessibility.