Gold-tin co-sensitized ZnO layered porous nanocrystals: enhanced responses and anti-humidity

Abstract

High responses and good selectivity are key sensing properties of metal oxide (MOX) gas sensors. However, it is still a major challenge for a single MOX gas sensor to achieve both of them. Specially, the research in the field of high performance gas sensors has been hindered by negative effects of the typical interference, relative humidity (RH). In this paper, we report the successful preparation of gold-tin co-sensitized ZnO layered porous nanocrystals (Au-5Sn-ZLPCs) via a sequential solvothermal reaction and deposition-reduction method. Based on Sn dopants sensitized ZLPCs, the introduction of Au decoration can act as a secondary sensitized element on the crystal surfaces of ZnO. The special synergy between noble metals and oxides can introduce additional catalytic effects to further improve sensing properties. As a result of Au-Sn co-sensitization, sensing properties of sensors towards reducing VOC gas were significantly enhanced, while those towards oxidizing ozone gas were different to each other. Besides the typical sensing properties including responses, operating temperature, response & recovery properties, etc., Au-Sn co-sensitized samples significantly reduced negative effects of RH on responses to both reducing and oxidizing gases (good anti-humidity).