Ultrafast Response/Recovery and High Selectivity of the H₂S Gas Sensor Based on α-Fe₂O₃ Nano-Ellipsoids from One-Step Hydrothermal Synthesis

Abstract

Ultrafast response/recovery and high selectivity of gas sensors are critical for real-time and online monitoring of hazardous gases. In this work, α-Fe2O3 nano-ellipsoids were synthesized using a facile one-step hydrothermal method and investigated as highly sensitive H2S sensing materials. The nano-ellipsoids have an average long axis diameter of 275 nm and an average short axis diameter of 125 nm. H2S gas sensors fabricated using the α-Fe2O3 nano-ellipsoids showed excellent H2S sensing performance at an optimum working temperature of 260 ℃. The response and recovery times were 0.8 s/2.2 s for H2S gas with a concentration of 50 ppm, which are much faster than those of H2S gas sensors reported in literature. The α-Fe2O3 nano-ellipsoid based sensors also showed a high selectivity to H2S compared to other commonly investigated gases including NH3, CO, NO2, H2, CH2Cl2 and ethanol. In addition, the sensors exhibited high response values to different concentrations of H2S with a detection limit as low as 100 ppb, as well as excellent repeatability and long-term stability.

Advanced development of metal oxide nanomaterials for H2gas sensing applications

“…The shorter response/recovery time, the better the sensor's performance. 114,115 The rapid speed of response is necessary for the detection of explosive gases especially for H 2 .…”

How Chemoresistive Sensors Can Learn from Heterogeneous Catalysis. Hints, Issues, and Perspectives

“…Another interesting hematite morphology has been recently published, consisting of microcubes for high-temperature (400 • C) detection of ethanol (100 ppm). Hematite nano-ellipsoids were used to detect down to 5 ppm H 2 S at 260 • C [148]. The comparison table presented by the authors, only concerning H 2 S sensing by hematite, is sufficient to testify about the flourishing sensing research on hematite sensors.…”

Synthesis and H2S Gas Sensing Characteritics of Nanostructured V2O5

“…Tại nhiệt độ 400 o C thời gian đáp ứng là dưới 10 giây và thời gian hồi phục là khoảng dưới 150 giây tại tất cả các nhiệt độ, nồng độ khí đo. Các kết quả về thời gian đáp ứng và hồi phục của vật liệu V2O5 cho ứng dụng cảm biến khí H2S của chúng tôi là ngắn hơn nhiều so với vật liệu CuO/ZnO và vật liệu Pd/CuO trong một số công bố trước đây cho cảm biến phát hiện khí H2S [16].…”