High-Performance Acetone Response in B-TiO2/SnS2 Heterojunction Nanosheets Driven by Visible Light at Room Temperature

High operating temperatures and limited responsiveness pose significant challenges for the application of TiO2 based gas sensors. In this study, low-temperature thermal reduction was utilized to generate oxygen vacancies on the surface of TiO2. Combining it with SnS2 nanosheets using a simple hydrothermal process, a B-TiO2/SnS2 heterostructure was fabricated to enhance its detection of acetone at room temperature. Experimental results demonstrate the B-TiO2/SnS2 sensor’s ability to detect acetone at room temperature under green light irradiation. In comparison to pure TiO2, the B-TiO2/SnS2 gas sensor shows significantly enhanced performance in detecting acetone, with higher response (15.1/20 ppm), faster response and recovery times (6.7 s/9.8 s), and a lower limit of detection (757 ppb). The mechanisms underlying the enhancement and light-sensing ability of the B-TiO2/SnS2 sensor are elucidated, emphasizing the impact of light absorption, specific surface area, and carrier separation facilitated by the heterojunction. Furthermore, the gas-sensing mechanism of the B-TiO2/SnS2 structure for superior acetone sensing is attributed to its larger adsorption energy according to density-functional theory (DFT) calculation. These findings provide valuable insights for developing room temperature gas sensors based on TiO2.