The use of heterojunctions is a promising solution to the problem of cross-sensitivity in gas sensors. In this work, a carbon monoxide sensor based on the CuO/TiO₂ heterojunction was designed and fabricated. Due to the good adsorption properties of CuO materials to CO, and the heterojunction interface charge transfer, the CuO/TiO₂ thin film sensor exhibits high sensitivity to CO at room temperature. The response is as high as 10.8–200 ppm CO, about 10 times its response to H₂. Interference from H₂ is greatly reduced by optimizing the structure of the CuO/TiO₂ heterojunction. This reliable detection of carbon monoxide with excellent discrimination against H₂ is of great significance for the development of CO gas sensors.

Low electronic conductivity and large volume changes during the (de) lithiation process are the two main challenges for ZnO anode materials used for lithium-ion batteries (LIB). Here, a free-standing, flexible, and binder-free LIB electrode composed of ZnO nanorods and carbon cloth (CC) is fabricated. This is then decorated with Ag nanoparticles and finally coated by an amorphous carbon layer to form the hybrid electrode: (C@(Ag&ZnO)). The voids among the nanorods are sufficient to accommodate the volume expansion of the ZnO while the flexible CC, which acts as the current collector, relieves the volume change-induced stress. The Ag nanoparticles are effective in improving the conductivity. This composite electrode shows excellent LIB performance with a stable long cycling life over 500 cycles with a reversible capacity of 1093 mAh g⁻¹ at a current density of 200 mA g⁻¹. It also shows good rate performance with reversible capacity of 517 mAh g⁻¹ under a high-current density of 5000 mA g⁻¹. In situ Raman spectroscopy is conducted to investigate the contributions of the amorphous carbon layer to the capacity of the whole electrode and the synergy between the CC and ZnO nanorods.