Rapid room-temperature H₂S detection based on Bi₂S₃/CuO heterostructures: the synergy of increased surface-adsorbed oxygen and a heterojunction effect

Transition metal dichalcogenides (TMDCs)/metal oxides are increasingly recognized as competitive sensing materials for detection at room temperature (RT). However, their unsatisfactory properties caused by low sensitivity, slow response, and weak discriminating ability towards interfering gases preclude their further applications in advanced sensing platforms. Herein, a Bi₂S₃/CuO heterostructure was demonstrated for H₂S detection with a highly sensitive rapid response at RT. The Bi₂S₃/CuO sensor exhibited a greatly improved response (31.2 to 1 ppm H₂S) with impressive response kinetics (7.5 s), surpassing that of pure Bi₂S₃ by a factor of 5 and 17, respectively. Besides, the sensor exhibits outstanding selectivity, repeatability, low detection limit (25 ppb), humidity tolerance and long-term stability. The distinctive enhancement of sensing capabilities primarily results from the synergistic influence of the heterostructure configuration and increased surface-adsorbed oxygen. This strategy of constructing heterostructures between a metal oxide and TMDC provides fundamental insights for developing room-temperature sensors.