Synthesis of three-dimensionally ordered macro/mesoporous C-doped WO3 materials: Effect of template sizes on gas sensing properties

Abstract

WO3-based materials have received substantial attention for their great potentials in workplace acetone detection and in breath acetone analysis. However, several key challenges, including acetone response, selectivity and material stability, should be further addressed before their practical applications. In this work, three-dimensionally ordered macroporous/mesoporous (3DOM) C-doped WO3 materials are synthesized and characterized extensively. The gas sensing properties of 3DOM C-doped WO3 materials are investigated and the calcination and operating temperature are optimized. Emphasis is placed on identifying how the pore sizes of 3DOM materials affecting gas sensing properties. The results show that the optimal material with 410 nm pore size exhibits the highest responses to acetone. Upon exposure to NH3, CO, methanol, ethanol, and formaldehyde, only slight responses are observed, implying an excellent selectivity. In addition, the sensor exhibits good repeatability and long-term stability. More attractively, it is found that the responses to acetone are related to the pore sizes of 3DOM C-doped WO3 materials. We suggest that the size of the basic building units in 3DOM structure plays a key role in acetone responses. The results gained herein may be useful for rational design of sensing materials with tunable gas sensing properties.