Selective gas detection using Mn3O4/WO3 composites as a sensing layer.

Yongjiao Sun,Wendong Zhang,Zhichao Yu,Jie Hu,Lin Chen,Gang Li,Pengwei Li,Serge Zhuivkov,Wenda Wang

doi:10.3762/bjnano.10.140

Abstract

Pure WO3 sensors and Mn3O4/WO3 composite sensors with different Mn concentrations (1 atom %, 3 atom % and 5 atom %) were successfully prepared through a facile hydrothermal method. As gas sensing materials, their sensing performance at different temperatures was systematically investigated for gas detection. The devices displayed different sensing responses toward different gases at specific temperatures. The gas sensing performance of Mn3O4/WO3 composites (especially at 3 atom % Mn) were far improved compared to sensors based on pure WO3, where the improvement is related to the heterojunction formed between the two metal oxides. The sensor based on the Mn3O4/WO3 composite with 3 atom % Mn showed a high selective response to hydrogen sulfide (H2S), ammonia (NH3) and carbon monoxide (CO) at working temperatures of 90 °C, 150 °C and 210 °C, respectively. The demonstrated superior selectivity opens the door for potential applications in gas recognition and detection.

Highlights

Tungsten oxide (WO3) is a highly stable, classical transition metal oxide
WO3 and Mn3O4/WO3 composites with different concentrations of Mn were prepared and characterized
Their selective gas sensing properties were investigated, and the measurement results show that the gas sensors based on Mn3O4/ WO3 composites presented outstanding selectivity to H2S, NH3 and carbon monoxide (CO) at the working temperatures of 90 °C, 150 °C and 210 °C, respectively

Summary

Introduction

Tungsten oxide (WO3) is a highly stable, classical transition metal oxide. When synthesized, WO3 usually presents a yellowish color because of its oxygen vacancy, which is an important reason why WO3 exhibits n-type semiconductor characteristics. The gas sensing performance under different temperatures to H2S, NH3 and CO were carried out on sensors based on pure WO3 and Mn3O4/WO3 composites.

Results

Conclusion