Sb-doped three-dimensional ZnFe2O4 macroporous spheres for N-butanol chemiresistive gas sensors

Abstract In this paper, the preparation process and gas sensing performance of Sb-doped three-dimensional spinel ferrite (3D ZnFe2O4) with well-assembled macroporous spherical structure have been investigated. Sb-doped 3D ZnFe2O4 macroporous spheres (MPs) were prepared through a one-step ultrasonic spray pyrolysis (USP) method by sacrificing self-assembly sulfonated polystyrene spheres (S-PSs). The interconnected macropores (an average pore size about 200 nm) can be observed in the as-prepared materials by SEM and TEM characterization, which provided the dual functions of accelerating the diffusion of gas molecules and providing more reactive sites. The XPS analysis showed that the element Sb existed as Sb5+ in doped samples. Compared with the pure 3D ZnFe2O4 MPs (response = 18), 0.5% Sb-doped sample presented the response of 35.5 to 100 ppm n-butanol at 250 °C, and also revealed excellent selectivity and long-term stability to n-butanol. The greatly enhanced sensing performance of Sb-doped simples can be attributed to the construction of 3D spheres with interconnected macroporous structures and the modification of Sb doping. The formation of p-n junctions at interface through Sb doping also improved the sensing performance for n-butanol. In addition, the relative sensing mechanism of Sb-doped 3D ZnFe2O4 MPs for n-butanol sensing has been discussed in detail.