Yung-Tai Hsu, Dieter Rahmadiawan, Shih-Chen Shi
Sulfur dioxide (SO₂), formaldehyde (HCHO), and carbon dioxide (CO₂) are common atmospheric pollutants that pose serious environmental and health risks. Although amine-based materials exhibit strong chemical affinity toward these gases, their practical performance is often limited by low surface area and weak sensing capability. In this work, a multifunctional oxide–polymer hybrid film was developed by integrating porous SiO₂ derive d from rice-husk ash into a polyvinyl alcohol (PVA) matrix and subsequently functionalizing the structure with m-phenylenediamine (MPDA). The porous oxide framework enhances gas accessibility, while the amine groups provide active adsorption sites. Gas–amine interaction mechanisms were investigated using Fourier-transform infrared spectroscopy and x-ray photoelectron spectroscopy, while adsorption capacity and sensing behavior were evaluated through quartz crystal microbalance, thermogravimetric analysis, and electrical resistance measurements. Distinct chemisorption pathways were identified, including sulfite formation with SO₂, imine formation with HCHO, and carbamate formation with CO₂. Pure MPDA adsorbed 76.5 mg g−1 of SO₂ and 89.3 mg g−1 of HCHO, whereas incorporation into the porous PVA/SiO₂ composite significantly enhanced adsorption capacities to 373.7 mg g−1 and 256.4 mg g−1, respectively, representing improvements of up to 490%. In addition to enhanced adsorption, the composite film exhibited a pronounced resistive sensing response, with electrical resistance decreasing from 5 MΩ to 0.1 MΩ upon SO₂ exposure. Both adsorption capacity and sensing performance remained stable during repeated cycling. These results demonstrate that the amine-functionalized porous PVA/SiO₂ hybrid film provides an effective platform for simultaneous gas capture and sensing, highlighting its potential as a sustainable material for advanced environmental monitoring technologies. © 2026 The Author(s). Published by IOP Publishing Ltd. Original content from this work may be used under the terms of the https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Department of Mechanical Engineering, National Cheng Kung University (NCKU), No. 1, University Road, Tainan, 70101, Taiwan; Department of Mechanical Engineering, Universitas Negeri Padang, Sumatera Barat, 25173, Indonesia
