Peng Qin,Shun-Hui Liu,Chong-Yu Wang,Xin Kang,Fengdong Qu,Zhen-Hua Ge,Xuetao Gan
Bismuth sulfide (Bi2S3) has significant potential for gas sensing applications, but its performance is often limited by insufficient active surface sites and suboptimal response efficiency. This study aims to overcome these challenges by developing a halogen-doped Bi2S3 nanostructure sensor array for detecting key gases associated with food spoilage. Halogen doping (Cl, Br, and I) substantially enhances the electronic structure and surface activity of Bi2S3, improving both its selectivity and adsorption properties for target gases. Theoretical calculations reveal that halogen doping not only introduces primary adsorption sites on Bi2S3 nanomaterials but also facilitates electron transfer between gas molecules and the material. The sensor array exhibits excellent sensitivity and accuracy in detecting NH3, H2S, and CO gases, achieving an estimation error of only 0.8% for NH3 concentration when combined with machine learning algorithms. Furthermore, the array successfully distinguishes 18 different gas concentrations and classes, achieving a classification accuracy of 97.8%. The study also investigates the impact of humidity on sensor performance, revealing that Bi2S3–Cl nanorods maintain high NH3 adsorption properties under humid conditions. Practical application in beef freshness detection confirms the sensor array’s potential for real-world use, offering innovative solutions for food quality monitoring.
Weiwei Meng,Lei Dai,Yuehua Li,Zhangxing He,Wei Meng,Huizhu Zhou,Ling Wang
Mixed potential NH 3 sensors with La 9.95 K 0.05 Si 5 AlO 26.45 (LKSAO) as the solid electrolyte and Bi 1-x Ag x VO 4- δ as the sensing electrode (SE) were developed. Bi 1-x Ag x VO 4- δ was produced by solid state reaction and then characterized by XRD, XPS, SEM and EDS. As revealed from the results, The BiVO 4 samples exhibit an unchanged crystalline structure after Ag doping molar amount x≤0.2, accompanied by the growth of the particle. The sensor based on Bi 1-x Ag x VO 4 - δ exhibit the noticeably enhanced sensing performance to NH 3 in contrast to the sensor using BiVO 4 , including its larger response potential (Δ V ) and higher sensitivity. For instance, the sensors based on BiVO 4 and Bi 0.8 Ag 0.2 VO 4 - δ at 400 °C exhibit the sensitivities of -28.1 and -77.3 mV/decade, respectively. Nevertheless, by Ag doping, there is no effective improvement of the anti-interference ability of the sensor against NO and NO 2 . To address the mentioned problem, CuO, NiO and La 0.8 Sr 0.2 MnO 3 (LSM) were used as reference electrodes (RE). As suggested from the results, using CuO and NiO as the reference electrodes can obviously reduce the cross-sensitivity of the sensor to NO and NO 2 , whereas the sensitivity slightly decrease.
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