Chemically modified discriminating gas sensors

金属氧化物气体传感器是小型设备- 2 mm x 2 mm，用于检测空气中的痕量气体。它们广泛用于汽车（排气和进气口）、气象气球、环境监测（填埋场）和臭氧检测。它们的工作原理是当暴露在气体中时，电阻会发生变化。这些传感器的问题在于，它们不能很好地区分不同气体的混合物-例如氨和甲烷都使传感器的电阻发生变化。对于这些传感器来说，要找到广泛的应用，它们需要能够在复杂气体混合物的存在下感测特定的目标气体。到目前为止，这还没有实现。这一提议将产生一种新型的传感器，该传感器在传统金属氧化物的顶部或嵌入金属氧化物中具有额外的识别传感器层。这一新层包含一种叫做沸石的材料--基本上是一种非常多孔的固体，可以让某些类型的气体渗透通过这种结构。沸石提供了增强的灵敏度，并根据其大小，形状和化学成分筛选气体分子。这些沸石层将给我们增强的灵敏度和最重要的选择性。通过结合不同类型的沸石，我们能够制造出一系列传感器，这些传感器的功能与人类的鼻子一样好，甚至更好。可以解决的具体问题包括：1检测受污染的水、食品、化学品和香水。棕色场地）。

Metal oxide gas sensors are small devices - 2 mm x 2mm that are used to detect trace gases in air. They are widely used in cars (exhausts and air intake vents), in weather balloons, in environmental monitoring (land fill sites) and in ozone detection. They work by showing a change in electrical resistance when exposed to a gas. The problem with these sensors is that they can't distinguish very well, if at all, mixtures of different gasses - for example ammonia and methane both give a change in resistance to the sensor. For these sensors to find wide spread application they need to be able to sense a specific target gas in the presence of a complex gas mixture. To date this has not been acheived. This proposal will generate a new type of sensor that has an additional discriminating sensor layer either on top of the traditional metal oxide or embedded within the metal oxide. This new layer contains a material called a zeolite- essentially a very porous solid that can let certain types of gases permeate through the structure. The zeolite gives enhanced sensitivity and sieves gas molecules on the basis of their size, shape and chemical composition. These zeolite layers will give us enhanced sensitivity and most importantly selectivity. By combining different types of zeolites we are able to make an array of sensors that can function as well as or better than the human nose. Specific problems that can be addressed include:1 Detection of contaiminated water, foodstuffs, chemicals and perfumes.2 A single breath detector that can analyse for a range of diseases and for alcohol/ drug content.3 Environmental monitoring (land fill, waste dump. brown field sites).