Implementing sensitive and fast ppb-level formaldehyde sensing at room temperature is still in extreme demand for practical indoor air quality monitoring. Herein, we developed a visible-light-sensitive and dipole-modified graphene-based nanocomposite ZnO_x@ANS-rGO for ultrasensitive trace formaldehyde sensing. The rich oxygen vacancy zinc oxide (ZnO_x) nanoparticles on graphene nanosheets provide OH-groups and edge sorption sites to facilitate the activation of adsorbed oxygen. Moreover, the supramolecular assembled 5-aminonaphthalene-1-sulfonic acid-modified graphene (ANS-rGO) nanosheets with donor–π–acceptor dipole served as an excellent conduction platform to transport and collect photo-generated electrons. Based on the collaboration of rich ZnO_x and ANS-rGO, the obtained sensor ZnO_x@ANS-rGO-0.1 showed the highest response (R_a/R_g = 1.58 to 1 ppm HCHO) among the MOS materials reported so far, and its limit of detection (LOD) can be as low as 5 ppb under 405 nm light illumination at RT. The outstanding efficiency and accuracy of the obtained gas sensor were confirmed by practical performance estimation in a 30 m³ chamber. The selectivity, long-term stability, repeatability and humidity resistance of the obtained sensors at RT were also revealed. The sensing mechanism based on the combination of visible-light activation and dipole modification was analyzed by the O-XPS, PL, in situ ATR-FTIR and charge density difference calculation.

中文翻译：

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基于可见光激活和偶极子修饰相结合的实用室温甲醛传感

在室温下实现灵敏、快速的 ppb 级甲醛检测仍然是实际室内空气质量监测的迫切需求。在此，我们开发了一种可见光敏感且偶极子改性的基于石墨烯的纳米复合材料 ZnO _x @ANS-rGO，用于超灵敏的痕量甲醛传感。石墨烯纳米片上的富氧空位氧化锌 (ZnO _x ) 纳米颗粒提供 OH 基团和边缘吸附位点，以促进吸附氧的活化。此外，具有供体-π-受体偶极子的超分子组装的5-氨基萘-1-磺酸改性石墨烯（ANS-rGO）纳米片作为传输和收集光生电子的极佳传导平台。基于富ZnO _x的合作和ANS-rGO，获得的传感器ZnO _x @ANS-rGO-0.1 在迄今为止报道的MOS材料中表现出最高的响应（R _a / R _g = 1.58 to 1 ppm HCHO），其检测限（LOD）可以在 RT 的 405 nm 光照下低至 5 ppb。通过在 30 m ³室中的实际性能评估证实了所获得的气体传感器的出色效率和准确性。还揭示了所获得的传感器在室温下的选择性、长期稳定性、可重复性和耐湿性。通过O-XPS、PL、原位分析基于可见光激活和偶极子修饰相结合的传感机制 ATR-FTIR 和电荷密度差计算。