A novel Cu-doped ZnO confined structure: Precisely preparation, and sensitization mechanism for ppb-level H2S gas detection

• Published in: Sensors and actuators. B, Chemical Chemical, 2024-09, Vol.414, p.135852, Article 135852
• Main Authors: Hu, Qingmin, Lu, Xilong, Gao, Tiange, Zhang, Jingtao, Dong, Zhenliang, Ma, Zhiheng, Wang, Xiaohong, Lu, Bo, Lv, Zhengxing, Xu, Jiaqiang
• Format: Article
• Language: English
• Subjects: Atomic layer deposition; Confined structure; Enhanced sensing mechanism; H2S gas sensor
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2024.135852

It is still highly desired and challengeable to design H2S sensor with high selectivity and sensitivity due to its toxicity and new application in biomarkers like monitoring halitosis. Here, we reported a novel confined structure as highly sensitive and selective H2S gas sensor. The sensing material was prepared with a HKUST-1 templated method by atomic layer deposition (ALD) ZnO decorated on HKUST-1 and calcination. The gas sensor exhibits a high gas sensitivity (Ra/Rg = 2.67 @ 2 ppm) with excellent selectivity to H2S. Furthermore, the obtained sensor shows ppb-level detection ability (Ra/Rg = 1.13 @ 0.1 ppm). Apart from releasing electrons by the oxidization of H2S on oxygen vacancies with adsorbed oxygen species O2− on ZnO surface (Langmuir-Hinshelwood mechanism), the Cu was proved to be the active sites, and would react with surficial S species. The suggestion was confirmed by operando XAS (X-ray adsorption spectrum) measurements combined with DFT calculations (Mars-van Krevelen mechanism). This work provides valuable insights for developing efficient sensing materials and understanding the sensing mechanism. •The different novel confined core-shell structure (CZO) were synthesized.•The CZO exhibits high sensitivity and selectivity to ppb level of H2S at 140 °C.•L-H and MvK mechanism were confirmed by operando XAS and DFT calculations.