Single-crystalline α-Fe2O3 oblique nanoparallelepipeds: High-yield synthesis, growth mechanism and structure enhanced gas-sensing properties

Abstract

In this paper, single-crystalline α-Fe₂O₃ oblique nanoparallelepipeds are fabricated in high yield via a facile surfactant-free hydrothermal method, which involves oriented aggregation and Ostwald ripening. The obtained nanocrystals have exposed facets of {012}, {01–4} and {−210} with a rhombohedral α-Fe₂O₃ structure. The gas sensors based on the as-synthesized α-Fe₂O₃ nanostructures exhibit high sensitivity, short recovery time, and good reproducibility in ethanol and acetone. The superiority of the gas-sensing properties of the obtained nanostructures should be attributed to the surface structure of the nanocrystals. The as-prepared α-Fe₂O₃ nanocrystals are significant for exploiting their other applications in the future.