Pioneering the Utilization of High-Entropy Oxides-Loaded In2o3 Nanofibers for the Engineering of a High-Performance Sensor Aimed at Ultra-Sensitive Detection of Low-Concentration H2s

Abstract

The chemical interaction between the target gas and adsorbed oxygen species is a critical factor significantly influencing the sensing performance of metal oxide semiconductor (MOS)-based gas sensors. Thus, we propose a design strategy: improving sensing performance by incorporating materials with exceptional catalytic properties into MOS-based sensing materials. High-entropy oxides (HEOs) have been the focus within catalysis. Accordingly, we proposed preparing HEOs/In2O3 composite nanofibers with varying HEOs loadings via electrospinning. The micro-nano structure, elemental composition, oxygen vacancies, and other physicochemical properties were characterized. Compared with pure In2O3 sensors, the incorporation of HEOs improved the response value and reduced response time. Especially, the sensor utilizing In2O3 nanofibers incorporated with the optimal amount of HEOs exhibited the highest response to 1 ppm H2S at 180°C, capable of detecting concentrations as low as 100 ppb. Furthermore, this sensor exhibited outstanding selectivity and remarkable long-term stability. The changes in physicochemical properties of In2O3 nanofibers, including the surface oxygen vacancy content, acidity/alkalinity and surface catalytic activity, which were induced by the incorporation of HEOs, are the crucial factors underlying the improvement of the sensor's performance in H2S detection. These results provide an excellent theoretical reference for the design of MOS-based sensitive materials to detect H2S gas.

Keywords: HEOs, H2S, sensor, In2O3