Facile synthesis of ZnFe2O4/α-Fe2O3 porous microrods with enhanced TEA-sensing performance.

Developing metal oxide nanocomposite with superior gas-sensing properties is an important subject in the field of gas sensor. In this paper, we reported a facile synthesis route for ZnFe 2 O 4 /α-Fe 2 O 3 porous microrods (PMRs) by using dual oxalates as sacrificial template. FeC 2 O 4 ·2H 2 O solid microrods (SMRs) were first synthesized by a chemical precipitation reaction between FeSO 4 ·7H 2 O and H 2 C 2 O 4 ·2H 2 O, which were then immersed in Zn 2+ aqueous solution to obtain the hybrid ZnC 2 O 4 ·2H 2 O/FeC 2 O 4 ·2H 2 O SMRs through the substitution reaction between Zn 2+ and Fe 2+ . After a proper annealing process, ZnFe 2 O 4 /α-Fe 2 O 3 PMRs were successfully prepared through the decomposition of ZnC 2 O 4 ·2H 2 O/FeC 2 O 4 ·2H 2 O SMRs. The prepared ZnFe 2 O 4 /α-Fe 2 O 3 PMRs are about 2–5 μm in length and 0.3–0.5 μm in diameter, and constructed by numerous loosely stacked nanoparticles with the size about 15 nm. The dominant pore size in ZnFe 2 O 4 /α-Fe 2 O 3 PMRs is around 10 nm. The results of gas-sensing tests indicates that through decorating the α-Fe 2 O 3 PMRs with ZnFe 2 O 4 , the response of the sensor towards TEA is remarkably improved. For example, the response of the composite sensor to 100 ppm TEA is as high as 42.4, which is about 20 times higher than that of the bare α-Fe 2 O 3 PMRs sensor (2.5). The enhanced TEA sensing mechanism of ZnFe 2 O 4 /α-Fe 2 O 3 PMRs was discussed in detail. [ABSTRACT FROM AUTHOR]