Biomimetic fabrication of α-Fe2O3 with hierarchical structures as H2S Sensor

A facile sol–gel method is developed for the fabrication of α-Fe2O3 with quasi-honeycomb like structures inherited from Papilio paris butterfly wings. The exquisite hierarchical architecture is faithfully maintained in α-Fe2O3 from the skeleton of butterfly wings at the levels from macro to nano-scales. When used as a chemical sensor, the obtained α-Fe2O3 replica (P-α-Fe2O3) showed a much higher performance than that of the compared α-Fe2O3 nanoparticles synthesized under the same condition without biotemplate (S-α-Fe2O3). The P-α-Fe2O3-based sensor has a sensitivity of 19.2–50 ppm H2S, which is four times more than that of S-α-Fe2O3, accompanied by a rapid response/recovery time within 1/10 s even at a relatively low working temperature of 180 °C. Compare to the S-α-Fe2O3, surface area of which cannot be detectable, the high sensing feature of P-α-Fe2O3 would be attributed to the relatively high-specific surface area 24.12 m2/g thus fabricated together with the unique 3D-network structures, which provide channel for the diffusion of H2S. This strategy is expected to be used in fabrication of other kinds of metal oxide with unique structures for the potential application in gas sensor.