The development of freestanding fiber-type chemiresistors, having high integration ability with various portable electronics including smart clothing systems, is highly demanding for the next-generation wearable sensing platforms. However, critical challenges stemming from the irreversible chemical sensing kinetics and weak reliability of the freestanding fiber-type chemiresistor hinder their practical use. In this work, for the first time, we report on the potential suitability of the freestanding and ultraporous reduced graphene oxide fiber functionalized with WO₃ nanorods (porous WO₃ NRs-RGO composite fiber) as a sensitive nitrogen dioxide (NO₂) detector. By employing a tunicate cellulose nanofiber (TCNF), which is a unique animal-type cellulose, the numerous mesopores are formed on a wet-spun TCNF-GO composite fiber, unlike a bare GO fiber with dense surface structure. More interestingly, due to the superior wettability of TCNF, the aqueous tungsten precursor is uniformly adsorbed on an ultraporous TCNF-GO fiber, and subsequent heat treatment results in the thermal reduction of a TCNF-GO fiber and hierarchical growth of WO₃ NRs perpendicular to the porous RGO fiber (porous WO₃ NRs-RGO fiber). The freestanding porous WO₃ NRs-RGO fiber shows a notable response to 1 ppm NO₂. Furthermore, we successfully demonstrate reversible NO₂ sensing characteristics of the porous WO₃ NRs-RGO fiber, which is integrated on a wrist-type wearable sensing device.

中文翻译：

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异质金属氧化物-石墨烯刺-布什单纤维作为独立的化学分析仪

具有独立集成的纤维型化学电阻器的开发对下一代可穿戴传感平台有很高的要求，这些电阻器与包括智能服装系统在内的各种便携式电子产品具有很高的集成能力。但是，由于不可逆的化学传感动力学和独立式纤维型化学电阻器的可靠性差而带来的严峻挑战阻碍了它们的实际应用。在这项工作中，我们首次报道了用WO ₃纳米棒（多孔WO ₃ NRs-RGO复合纤维）作为敏感的二氧化氮（NO ₂）功能化的独立式和超多孔还原氧化石墨纤维的潜在适用性。）检测器。通过使用一种独特的动物型纤维素被膜纤维素纳米纤维（TCNF），与具有致密表面结构的裸GO纤维不同，在湿纺TCNF-GO复合纤维上形成了许多中孔。更有趣的是，由于TCNF的优异润湿性，水性钨前驱物均匀地吸附在超多孔TCNF-GO纤维上，随后的热处理导致TCNF-GO纤维的热还原和垂直于WO ₃ NR的分层生长多孔RGO纤维（多孔WO ₃ NRs-RGO纤维）。独立的多孔WO ₃ NRs-RGO纤维显示出对1 ppm NO ₂的显着响应。此外，我们成功证明了可逆的NO ₂集成在腕式可穿戴传感设备上的多孔WO ₃ NRs-RGO纤维的传感特性。