Abstract
Developing low-cost, highly responsive low-temperature H2S sensors is critical due to rising air pollution, as well as the high energy consumption and safety risks associated with conventional semiconductor sensors. Non-stoichiometric NiOx offers enhanced carrier concentration and active sites via nickel vacancies, thereby improving low-temperature sensitivity. Composite sensors were fabricated by incorporating various mass fractions of the topological insulator Bi2Te3 into NiOx. The 10% Bi2Te3@NiOx sensor delivered the best performance [11.81 response to 10 ppm H2S at 90 °C, 30% relative humidity (RH)], surpassing most reported H2S sensors. Its sensitivity is attributed to enhanced carrier mobility and Bi2Te3 Dirac point shift upon H2S physisorption. With excellent H2S selectivity and stability, this composite offers a safer, energy-efficient, low-temperature alternative to high-temperature sensors.