Enhanced selective acetone-sensing performance of hierarchical hollow SnO2/α-Fe2O3 microcubes

Abstract

Template-controlled syntheses via metal–organic frameworks (MOFs) have emerged as a general strategy to fabricate metal oxides with tailored porous structures. Here, novel hierarchical SnO₂/α-Fe₂O₃ hollow microcubes have been obtained by post-loading of Sn²⁺ ions on the surface of Fe₄(Fe(CN)₆)₃ microcubes and a subsequent thermolysis route. The as-formed hierarchical SnO₂/α-Fe₂O₃ composites exhibit remarkable selective acetone-sensing properties, in which the optimum composition of SnO₂/α-Fe₂O₃ with Sn : Fe = 1.5 exhibits the best response towards 200 ppm acetone gas under the operating temperature of 270 °C (with gas response R_a/R_g = 9.3), with a fast response/recovery speed (6 s/7 s), as well as excellent reproducibility for at least 15 days without a significant change in response. The applied strategy provides a general and controllable method to access other hierarchically structured multi-metal oxide architectures with intriguing morphologies and adjustable sensing properties.