In situ growth of Ag-loaded hierarchical NiO microspheres for enhanced H2S-sensing performance and the sensing mechanism

• Published in: Applied surface science 2025-03, Vol.685, p.162033, Article 162033
• Main Authors: Fu, Quan-Tao, Yu, Hai-Xia, Yang, Ming-Rui, Xu, Ying-Ming, Zhao, Dan, Bai, Xiao-Jing, Wang, Ping, Huo, Li-Hua, Zhang, Wen-Zhi, Sui, Li-Li
• Format: Article
• Language: English
• Subjects: Ag loading; H2S-sensing; Hierarchical structure; NiO microspheres
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2024.162033

Hierarchical and polyporous Ag/NiO microspheres were in situ grown on ceramic tubes by one-step solvothermal reaction with subsequent calcination. Remarkably, the 2.25 at% Ag decorated NiO sensors demonstrated higher sensitivity, better selectivity and faster recovery speed to trace H2S at 92 °C in comparison with the pristine NiO ones. [Display omitted] •Hierarchical Ag/NiO microspheres were in situ grown on Al2O3 tubes by one-step solvothermal route.•Loading with Ag resulted in enhanced response kinetics towards H2S for Ag/NiO microspheres sensors.•Gas-sensing mechanism for Ag/NiO to low concentration of H2S is deduced as the oxidation of H2S into SO2. Construction of noble metal-functionalized hierarchical metal oxides is an effective avenue to achieve accurate and rapid detection of hazardous gases. Herein, Ag-loaded hierarchical NiO structures were successfully in situ grown on ceramic tubes via a simple one-step solvothermal method. Morphological characterization demonstrated that the hybrid nanomaterials were hierarchical microspheres of 600–900 nm, which were constructed from interlaced nanosheets in the thickness of 35–45 nm. And the Ag nanoparticles (NPs) were uniformly deposited on the surface of NiO microspheres. The sensors based on the 2.25 at% Ag-loaded NiO microspheres exhibited superior H2S-sensing performance at 92 °C. In particular, the response value of 510.1–10 ppm H2S increased as high as 14.7 times compared to the NiO ones. Besides, Ag-dopant decreased the recovery time of 10 ppm H2S from 14.4 s to 3.2 s, with the lowest detection limit of 0.001 ppm. The enhanced sensing performance of Ag/NiO microspheres sensors should be attributed to the chemical sensitization of Ag-dopant, the in situ growth pattern and construction of 3D hierarchical structures, which provide abundant active sites for gas molecules adsorption and the consequent electron transfer, endowing the remarkable H2S-sensing performance to Ag/NiO microspheres.