Cu-doped SnO2/rGO nanocomposites for ultrasensitive H2S detection at low temperature
Tingting Chen, Jianhai Sun, Ning Xue, Wen Wang, Zongchang Luo, Qinqin Liang, Tianye Zhou, Hao Quan, Haoyuan Cai, Kangsong Tang, Kaisheng Jiang
Abstract
Abstract Hydrogen sulfide (H 2 S) detection remains a significant concern and the sensitivity, selectivity, and detection limit must be balanced at low temperatures. Herein, we utilized a facile solvothermal method to prepare Cu-doped SnO 2 /rGO nanocomposites that have emerged as promising candidate materials for H 2 S sensors. Characterization of the Cu-SnO 2 /rGO was carried out to determine its surface morphology, chemical composition, and crystal defects. The optimal sensor response for 10 ppm H 2 S was ~1415.7 at 120 °C, which was over 320 times higher than that seen for pristine SnO 2 CQDs ( R a / R g = 4.4) at 280 °C. Moreover, the sensor material exhibited excellent selectivity, a superior linear working range ( R 2 = 0.991, 1–150 ppm), a fast response time (31 s to 2 ppm), and ppb-level H 2 S detection ( R a / R g = 1.26 to 50 ppb) at 120 °C. In addition, the sensor maintained a high performance even at extremely high humidity (90%) and showed outstanding long-term stability. These superb H 2 S sensing properties were attributed to catalytic sensitization by the Cu dopant and a synergistic effect of the Cu-SnO 2 and rGO, which offered abundant active sites for O 2 and H 2 S absorption and accelerated the transfer of electrons/holes.