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

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) demonstrate exceptional catalytic activity attributed to the synergistic effects among their constituent elements and have been the focus within catalysis. Accordingly, we proposed preparing HEOs/In 2 O 3 composite nanofibers with varying HEOs loadings via electrospinning. The micro/nanostructure, elemental composition, oxygen vacancies, and other physicochemical properties were characterized. Compared with pure In 2 O 3 sensors, the load of HEOs improved the response value and reduced response time. Especially, the sensor utilizing In 2 O 3 nanofibers loaded with the optimal amount of HEOs exhibited the highest response to 1 ppm H 2 S at 180 °C, capable of detecting concentrations as low as 100 ppb. Furthermore, this sensor exhibited outstanding selectivity and good long-term stability. The changes in physicochemical properties of In 2 O 3 nanofibers, including the surface oxygen vacancy content, acidity/alkalinity and surface catalytic activity, which were induced by the load of HEOs, are the crucial factors underlying the improvement of the sensor's performance in H 2 S detection. These results provide an excellent theoretical reference for the design of MOS-based sensitive materials to detect H 2 S gas.