Humidity-Sensing Performance of 3DOM WO3 with Controllable Structural Modification

The development of humidity sensors with excellent sensing performance is a great challenge in the field of material chemistry. Here, we synthesized 3DOM WO₃ nanomaterials through a poly(methyl methacrylate) template method, and first, we applied it to humidity measurement. For the goal of better sensing performance, the structural modification of Li/K-codoping was adopted, and the test results showed that Li/K-codoped 3DOM WO₃ possessed highly improved humidity sensing performances, such as high response, low-humidity hysteresis, good long-term stability, great repeatability, decent response, and recovery properties. To deeply understand the great effect of Li/K-codoping on sensing performance, the pure, Li-monodoped, and Li/K-codoped 3DOM WO₃-based humidity sensors were compared, and we found that the structure defects and adsorbed oxygen as well as the co-effect of Li/K dopants were key factors for the improved sensing performance. Additionally, a possible humidity sensitive mechanism was proposed to further study the promotion effect of Li/K-codoping on humidity sensing process.