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 TiO 2 based gas sensors. In this study, low-temperature thermal reduction was utilized to generate oxygen vacancies on the surface of TiO 2 . Combining it with SnS 2 nanosheets using a simple hydrothermal process, a B-TiO 2 /SnS 2 heterostructure was fabricated to enhance its detection of acetone at room temperature. Experimental results demonstrate the B-TiO 2 /SnS 2 sensor’s ability to detect acetone at room temperature under green light irradiation. In comparison to pure TiO 2, the B-TiO 2 /SnS 2 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-TiO 2 /SnS 2 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-TiO 2 /SnS 2 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 TiO 2 .