Highly Responsive H₂S Sensors Based on Different Fe₂O₃ Nanomaterials Loading With CuO

The continuous increase in industrial exhaust emissions has led to rising atmospheric hydrogen sulfide (H<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>S) concentrations, posing significant threats to both environmental safety and human health. In this study, four morphologically distinct Fe<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>-based gas sensors were synthesized via different surfactantassisted hydrothermal method, among which the nanorod-structured Fe<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> exhibited optimal sensing properties. Loading CuO into this form of iron oxide sensing material to construct p-n heterojunctions, with systematic investigation of the influence of varying CuO loading concentrations on sensor performance. Systematic investigation revealed that CuO modification significantly improved the sensor response characteristics. The optimized sensor with 15 wt% CuO loading demonstrated exceptional performance, exhibiting an ultrahigh response value of 1780 toward 100 ppm H<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>S at the operating temperature of 125°C, along with a rapid response time of 9 s. It provides a reasonable idea for the design of highly responsive hydrogen sulfide sensors.