Hierarchical porous materials have a potential for sensitive and fast gas detection due to their large specific surface area (SSA) and good gas diffusion. Herein, a facile optochemical sensor capable of generating visually detectable gaseous hydrogen chloride (HCl) was reported. The sensor used 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPPH₂) as an optical probe, and the optical probe was immobilized in the hierarchical porous silica nanofiber membrane which was fabricated by the electrospinning method. The presence of mesopores and macropores promoted the gas adsorption and diffusion of the TCPPH₂ functionalized hierarchical porous silica nanofiber membrane (TCPPH₂–SiO₂ HPNFM). As a consequence, the TCPPH₂–SiO₂ HPNFM sensor exhibited a highly sensitive and time-efficient response for HCl gas detection. The results indicated a detection limit of 17 ppb and a response time of 5 s. A pseudo-second-order rate constant of 8.55 × 10^–5 was observed because of the mesopores, which generated a large SSA and high pore volume. The sensor also had a vivid color variation from cameo to green and a good reversibility, which had a promising alternative to develop a low-cost HCl gas-sensing system.

中文翻译：

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卟啉官能化的多孔二氧化硅纳米纤维膜，用于快速检测HCl气体

多层多孔材料具有较大的比表面积（SSA）和良好的气体扩散性，因此具有灵敏且快速的气体检测潜能。在此，报道了一种能够产生视觉上可检测的气态氯化氢（HCl）的简便的光化学传感器。该传感器使用5,10,15,20-四（4-羧基苯基）卟啉（TCPPH ₂）作为光学探针，并将该光学探针固定在通过电纺丝法制备的分级多孔二氧化硅纳米纤维膜中。中孔和大孔的存在促进了TCPPH ₂功能化的分级多孔二氧化硅纳米纤维膜（TCPPH ₂ -SiO ₂ HPNFM）的气体吸附和扩散。结果，TCPPH ₂–SiO ₂ HPNFM传感器对HCl气体检测显示出高度灵敏且高效的响应。结果表明检测限为17 ppb，响应时间为5 s。由于中孔，观察到的伪二级速率常数为8.55×10 ^–5，它产生了很大的SSA和高孔隙率。该传感器还具有从浅驼色到绿色的生动颜色变化以及良好的可逆性，这是开发低成本HCl气体传感系统的有希望的替代方法。