@article{Zhang2025, 
author = {Yeguang Zhang and Zichang Zhang and Guangqiang Chen and Junhuan Liu and Feihu Li and Bita Farhadi and Peng Wang and Haoxiang Zhang and Shengzhong (Frank) Liu},
title = {Bioinspired 2D inverse opal PANI/Ag composites for ultra-fast room-temperature ammonia sensing: Synergistic vortex effects and metal catalysis mechanisms},
year = {2025},
journal = {Nano Research},
volume = {18},
number = {10},
pages = {94907918},
keywords = {density functional theory (DFT), vortex effect, wearable ammonia sensor, 2D inverse opal (2DIO), in-situ Fourier transform infrared (in-situ FT-IR) spectroscopy},
url = {https://www.sciopen.com/article/10.26599/NR.2025.94907918},
doi = {10.26599/NR.2025.94907918},
abstract = {The development of highly sensitive and rapid-response/recovery room-temperature NH3 sensors is critically demanded for environmental monitoring and healthcare diagnostics, yet remains scientifically challenging. Inspired by the two-dimensional ordered macroporous structure of peacock feathers, two-dimensional inverse opal (2DIO) polyaniline/silver (PANI/Ag) composites were fabricated via a sacrificial templating method. By integrating the advantages of gas diffusion of highly ordered macroporous structures with the catalytic activity of Ag, significant improvements in NH3 sensing performance were achieved. Computational fluid dynamics (CFD) simulations demonstrated that the 2DIO structure induced vortex effects, which significantly reduced the gas velocity. Concurrently, macroporous channels (~ 240 nm diameter) enhanced adsorption/desorption kinetics. The fabricated 2DIO PANI/Ag sensor exhibited a remarkable response of 1153% to 100 ppm NH3, with ultra-fast response/recovery times of 3 s/56 s, exhibiting a 420-fold improvement in response/recovery speed compared to pure PANI (126 s/325 s). A further developed wearable detection module successfully discriminated exhalation signals between simulated chronic kidney disease (CKD) patients and healthy individuals, providing a new strategy for noninvasive medical diagnosis. In-situ Fourier transform infrared spectroscopy (in-situ FT-IR) real-time tracking of NH3 adsorption/desorption processes confirms a chemisorption-dominated sensing mechanism. Density functional theory (DFT) calculations showed that the charge transfer at the PANI/Ag interface enhanced the adsorption of NH3, which significantly enhanced the molecular affinity. This study provides a viable pathway for developing high-performance flexible NH3 gas sensors through an interdisciplinary approach combining structural bionics, simulation optimization, theoretical analysis, and experimental validation.}
}