Portable and inexpensive gas sensors are essential for the next generation of non-invasive medical diagnostics, smart air quality monitoring & control, human search & rescue and food quality assessment to name a few of their immediate applications. Therein, analyte selectivity in complex gas mixtures like breath or indoor air remains the major challenge. Filters are an effective and versatile, though often unrecognized, route to overcome selectivity issues by exploiting additional properties of target analytes (e.g., molecular size and surface affinity) besides reactivity with the sensing material. This review provides a tutorial for the material engineering of sorption, size-selective and catalytic filters. Of specific interest are high surface area sorbents (e.g., activated carbon, silica gels and porous polymers) with tunable properties, microporous materials (e.g., zeolites and metal–organic frameworks) and heterogeneous catalysts, respectively. Emphasis is placed on material design for targeted gas separation, portable device integration and performance. Finally, research frontiers and opportunities for low-cost gas sensing systems in emerging applications are highlighted.

中文翻译：

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通过过滤器实现高选择性气体传感

便携式且廉价的气体传感器对于下一代无创医疗诊断、智能空气质量监测和控制、人类搜索和救援以及食品质量评估至关重要，仅举几例它们的直接应用。其中，复杂气体混合物（如呼吸或室内空气）中的分析物选择性仍然是主要挑战。除了与传感材料的反应性之外，过滤器是通过利用目标分析物的附加特性（例如，分子大小和表面亲和力）来克服选择性问题的一种有效且通用的途径，尽管通常未被认识到。这篇综述为吸附、尺寸选择和催化过滤器的材料工程提供了一个教程。特别感兴趣的是高表面积吸附剂（例如、活性炭、硅胶和多孔聚合物），分别具有可调性能、微孔材料（例如沸石和金属有机骨架）和多相催化剂。重点放在有针对性的气体分离、便携式设备集成和性能的材料设计上。最后，强调了新兴应用中低成本气体传感系统的研究前沿和机遇。