Nowadays the detection of unwanted volatile compounds in air is increasingly important in a wide range of fields. Metal oxide nanosensors are extremely small and cheap devices that could be integrated in any application, but their single resistance response make them non-selective. For this reason, sensor arrays are used where pollutant recognition is needed. Unfortunately, these electronic noses, consisting of different active materials, are complex and expensive. Here, we present a simple visual nanosensor that can detect and recognize selectively several volatile compounds at a relatively low temperature (200–300 °C). The dynamic resistance of a conductometric NiO nanosensor is simply transformed in a visual output that allows to recognize different gases and their concentration with a quick look. This way, one single nanostructured metal oxide can act as a sensitive and selective electronic nose, using the powerful post-processing given by the human eyes and brain. The sensor has proven to discriminate 8 different gases diluted in air (1 oxidizing and 7 reducing) and their respective concentration.

如今，在广泛的领域中，检测空气中有害的挥发性化合物变得越来越重要。金属氧化物纳米传感器是非常小巧且便宜的设备，可以集成在任何应用中，但是它们的单电阻响应使其成为非选择性的。因此，在需要污染物识别的地方使用传感器阵列。不幸的是，由不同的活性材料组成的这些电子鼻是复杂且昂贵的。在这里，我们介绍了一个简单的视觉纳米传感器，它可以在相对较低的温度（200–300°C）下选择性地检测和识别几种挥发性化合物。只需简单地将电导率NiO纳米传感器的动态电阻转换为可视输出，即可快速识别各种气体及其浓度。这条路，利用人眼和大脑提供的强大的后处理功能，一种单一的纳米结构金属氧化物可以充当敏感的选择性电子鼻。事实证明，该传感器可区分8种在空气中稀释的气体（1种被氧化，7种被还原）以及它们各自的浓度。