Ultra-thin nanosheets-assembled hollowed-out hierarchical α-Fe2O3 nanorods: Synthesis via an interface reaction route and its superior gas sensing properties

• Hollowed-out hierarchical α-Fe2O3 nanorods were firstly synthesized via the interfacial-reaction of FeC2O4·2H2O with NaOH.
• The α-Fe2O3 nanorods were assembled by interlaced ultrathin nanosheets with thickness of around 3 nm.
• The α-Fe2O3 nanorods exhibit high response to acetone and ethanol; especially, the response/recovery time of the gas sensor to 100 ppm acetone and ethanol are 0.4/2.4 s and 0.8/3.2 s, respectively.

Because of the lack of proper pore structure, the development of ultra-fast responding and recovering gas sensors materials remains a challenge. Herein, we report the synthesis of hollowed-out hierarchical α-Fe2O3 nanorods via the interfacial-reaction of FeC2O4·2H2O with NaOH for the first time. The as-prepared hierarchical nanorods assembled by interlaced ultrathin nanosheets (with thickness of around 3 nm) possess large specific surface area and novel open-style pore structure, which endow it with large amount of gas adsorption and rapid gas diffusion. Gas sensing measurement revealed that the hollowed-out hierarchical α-Fe2O3 nanorods exhibit high response and ultra-fast response/recovery characteristics to acetone and ethanol (the response/recovery time of the gas sensor to 100 ppm acetone and ethanol are 0.4/2.4 s and 0.8/3.2 s, respectively). As demonstrated, the hollowed-out hierarchical α-Fe2O3 nanorods assembled by ultrathin nanosheets which synthesized via a new strategy are highly promising for real-time monitoring gas sensor which has not only high response but also ultra-fast responding and recovering behaviors.