High-entropy oxide hollow sphere/In2O3 nanofiber composites for high-performance H2S sensing with ppb-level detection limit

For metal oxide semiconductor gas sensors, surface reactions are central to their sensing performance. Herein, we propose a strategy for constructing high-performance composite sensing materials by introducing HEOs hollow spheres. Employing In 2 O 3 nanofibers as the sensing substrate leverages their favorable charge carrier transport characteristics, while the innovative incorporation of HEOs hollow spheres with unique physicochemical properties effectively enhances H 2 S detection. Through electrospinning technology, we successfully fabricated HEOs/In 2 O 3 composite nanofibers with different HEOs loading amounts. The optimal sample exhibited an ultrahigh response of 3200 toward 1 ppm H 2 S at 120°C, accompanied by a substantially shortened response time of 31 s and a low detection limit of 5 ppb. Notably, the operating temperature was reduced from 180°C to 120°C, while excellent selectivity and long-term stability were maintained. Characterization results demonstrate that the decoration of HEOs hollow spheres not only modulates the microscopic morphology but also enriches the surface oxygen vacancy concentration, which serves as the critical factor for the enhanced H 2 S sensing performance of the composite sensor, providing a novel platform and theoretical foundation for the rational design of next-generation high-performance H 2 S sensors.