LaFeO3 porous hollow micro-spindles for NO2 sensing

LaFeO3 micro-spindles with intriguing structural characteristics were synthesized using cyano-bridged coordination polymers as sacrificial templates. Within a longitudinal dimension of less than 5 mu m, each micro-spindle features a hollow center contained in a mesoporous shell with hexagonal cross section. Conductometric gas sensors developed from these micro-spindles demonstrate a comprehensively improved NO2-sensing performance over other-reported LaFeO3 devices, including lower operating temperature (155 degrees C), higher sensitivity (response of 81.4% under 5 ppm) and expedited response and recovery (40 s/329 s). Such performance is enabled by a semiconducting mechanism governed by the formation and catalytic dissociation of nitrite species during NO2 adsorption on LaFeO3, facilitated by the special hierarchical structure of the micro-spindle.