In this study, a new type of lead-free double perovskite Cs 2 TeBr 6 combined with metal-free semiconductor g-C 3 N 4 heterojunction is constructed and used for photocatalytic CO 2 reduction for the first time. The S-scheme charge transfer mechanism between Cs 2 TeBr 6 and g-C 3 N 4 is systematically verified by X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR) and in situ Fourier infrared spectroscopy(FT-IR). The formation of S-type heterojunction makes the photocatalyst have higher charge separation ability and highest redox ability. The results show that 5%-CTB/CN heterojunction material has the best photocatalytic reduction effect on CO 2 under visible light irradiation. After 3 h of illumination, the yield of CO and CH 4 are 468.9 µmol g −1 and 61.31 µmol g −1 , respectively. The yield of CO is 1.5 times and 32 times that of pure Cs 2 TeBr 6 and g-C 3 N 4 , and the yield of CH 4 is doubled compared with pure Cs 2 TeBr 6 . However, g-C 3 N 4 almost does not produce CH 4 , which indicates that the construction of heterojunction helps to further improve the photocatalytic performance of the material. This study provides a new idea for the preparation of Cs 2 TeBr 6 /g-C 3 N 4 heterojunction and its effective interfacial charge separation.
Halide perovskite (HP) materials have attracted much attention in recent years in the fields of smart home and medical detection due to their low fabrication cost, simple preparation process, controllable properties, and adjustable morphology. However, the inherent instability and toxicity of lead has been barriers limiting the practicality in electronical devices. Here, we demonstrate a high-performance impedimetric humidity sensor based on an all-inorganic lead-free HP Cs 2 TeBr 6 for the first time. The Cs 2 TeBr 6 sensor achieves ultra-high response value of 5 orders of magnitude (8.89 × 10 5 ) at 11–97 % relative humidity (RH), short response time (4 s), favorable repeatability, and good long-term stability. Moreover, high humidity sensing performance enables the Cs 2 TeBr 6 sensor to enjoy great potentials in real-time touchless human breath and finger detections. In addition, the mechanism of moisture sensitivity is explained by complex impedance spectra at different humidity levels. This work contributes an attracting candidate material for humidity sensors, and furthermore provides new insights into next-generation sensory devices using lead-free HPs for human-related detections.
危险品化学品经营许可证（带存储）