Synthesis and optical hydrogen gas sensing properties of ZnO/WO3 composite films with hierarchical structure

Abstract

In this paper, the ZnO/WO3 composite films with hierarchical structure were successfully prepared by the colloidal template method and solvothermal method. The ZnO/WO3 composite films exhibit ordered porous ZnO and slender WO3 nanowires structure. The pore diameter of the porous ZnO layer is ∼1070 nm. The diameter and length of WO3 nanowires are 7–16 nm and 450–520 nm, respectively. After Pt catalyst was loaded by magnetron sputtering, the ZnO/WO3 composite films exhibit a shorter response time of 11.2 s to 4 % H2 at room temperature, which is half of that of WO3 nanowire films reported in the exist literatures. It’s attributed to the high aspect ratio of WO3 nanowires and open porous structure that lead to excellent synergistic effects for the diffusion of H2 gas and H atoms. The transmittance of ZnO/WO3 composite films can decrease by 61.8 % at 1500 nm wavelength. And the ZnO/WO3 composite films can detect different H2 concentrations at room temperature.