Microwave-Assisted Hydrothermal/Impregnation Synthesis of Cu2O‑Decorated rGO/In2O3 Nanorices for Sensitive SO2 Gas Sensors.

In the present development, Cu₂O-decorated reduced graphene oxide/indium oxide (rGO/In₂O₃) nanorices with Cu contents of 0–1.5 wt % were synthesized by a microwave-assisted hydrothermal method combined with impregnation and studied for gas-sensing applications toward SO₂. The material characterization results revealed that 3–5 nm Cu₂O secondary nanoparticles were uniformly decorated on porous In₂O₃ nanorices mixed with rGO sheets. Based on systematic gas-sensing measurements, Cu₂O decoration on rGO/In₂O₃ nanorices with the optimal Cu content of 1.0 wt % provided a considerably improved SO₂ response of 11.1 to 5 ppm SO₂, which was approximately 3.3-fold as high as that of pristine rGO/In₂O₃ nanorices (3.4) at an optimal temperature of 200 °C. Additionally, high SO₂ selectivity was attained against NO₂, NO, CO, H₂S, C₂H₅OH, C₂H₄, H₂, and NH₃. Moreover, the Cu₂O-rGO/In₂O₃ sensors displayed low humidity sensitivity, good repeatability, and satisfactory long-term stability. Therefore, Cu₂O-decorated rGO/In₂O₃ nanorices represented one of the most promising SO₂ sensors for environmental and practical applications. [ABSTRACT FROM AUTHOR]