Highly sensitive and selective detection against specific target gases, especially at low-ppb (part per billion) level, remain a great number of challenges in gas sensor applications. In this paper, we first present an ordered mesoporous NiFe₂O₄ for highly sensitive and selective detection against low-ppb toluene. A series of mesoporous NiFe₂O₄ materials were synthesized by templating from mesoporous silica KIT-6 and its framework thickness was reduced from 8.5 to 5 nm by varying the pore size of KIT-6 from 9.4 to 5.6 nm, accompanied with the increase of the specific surface area from 134 to 216 m² g⁻¹. The ordered mesoporous NiFe₂O₄ with both ultrathin framework of 5 nm and large specific surface area of up to 216 m² g⁻¹ exhibits a highest response (R_gas/R_air − 1 = 77.3) toward 1,000 ppb toluene at 230 °C and is nearly 7.3 and 76.7 times higher than those for the NiFe₂O₄ replica with thick framework and its bulk counterpart respectively, which also possesses a quite low limit of detection (<2 ppb), and good selectivity.

针对特定目标气体的高灵敏度和选择性检测，尤其是低 ppb（十亿分之一）水平，仍然是气体传感器应用中的大量挑战。在本文中，我们首先提出了一种用于对低 ppb 甲苯进行高灵敏度和选择性检测的有序介孔 NiFe ₂ O _{4 。}以介孔二氧化硅KIT-6为模板合成了一系列介孔NiFe ₂ O ₄材料，通过改变KIT-6的孔径从9.4 nm到5.6 nm，骨架厚度从8.5 nm减小到5 nm，同时增加了比表面积为134至216m ²  g ^-1。有序介孔NiFe ₂ O ₄^{具有 5 nm 的超薄框架和高达 216 m 2}  g ⁻¹的大比表面积，在 230 °C 下对 1,000 ppb 甲苯表现出最高响应 ( R _gas / R _air  − 1 = 77.3)，接近 7.3 和 76.7分别比具有厚框架的 NiFe ₂ O ₄复制品及其块状对应物高出 1 倍，后者还具有相当低的检测限 (<2 ppb) 和良好的选择性。