Flower sphere-like Cu2O/CuO heterostructure derived from Cu-coordination polymer for enhancing Cl2 sensing at low-power consumption

It is necessary to achieve highly sensitive and low temperature detection of Cl₂ for the protection of the environment and human life and health. How to achieve sensitive detection of Cl₂ at low temperature remains a challenge. The construction of heterojunction is beneficial for promoting carrier transfer, increasing active sites, thus effectively improving sensing performance of materials. In this study, the flower sphere-like Cu₂O/CuO composite with p-p heterojunction was obtained by using Cu-CPs as precursor followed with sintering treatment. The Cu₂O/CuO sensor exhibits high response (S=405) to 10 ppm Cl₂ at low temperature (50 ^oC), the response/recovery time is 50 s/2420 s. At the same time, the Cu₂O/CuO sensor has a low detection limit (50 ppb) and good long-term stability (60 days). The characterization results, e.g. electron paramagnetic resonance (EPR), O₂/Cl₂-temperature programmed desorption (O₂/Cl₂-TPD), X-ray photoelectron spectroscopy (XPS) etc., reveal that oxygen vacancy effectively promotes the increase of surface adsorbed oxygen, the formation of p-p heterojunction not only modulates the electronic properties of Cu₂O/CuO but also provides abundant adsorption sites for gas. The synergistic effect of the above factors makes Cu₂O/CuO composite exhibit satisfactory Cl₂ sensing performance.