Synergistic Schottky barrier effect in SrTiO3/Ti3C2Tx for near-room temperature toluene detection

The detection of hazardous volatile aromatic compounds (VOCs), such as toluene, remains a critical challenge in environmental, industrial, and household monitoring for human health protection. Herein, SrTiO 3 and SrTiO 3 /MXene heterostructures were synthesized using a simple hydrothermal approach, while the Ti 3 C 2 T x (MXene) was synthesized following the LiF–HCl etching method. Their structural, optical, and gas-sensing properties were thoroughly examined. The SrTiO 3 showed a wide band gap of 3.20 eV, while the MXene and SrTiO 3 /MXene heterostructure displayed narrower and intermediate band gaps of 0.93 eV and 2.82 eV, respectively. Photoluminescence results demonstrated higher emission intensity in the heterostructure, indicating increased surface defects and oxygen vacancies that served as active sites for gas adsorption. Gas-sensing analyses revealed that SrTiO 3 /MXene significantly outperformed individual components in detecting 100 ppm toluene vapors at 50 °C. This enhanced response is due to the combined effects of defect-driven oxygen adsorption and efficient charge transport via Ti 3 C 2 T x layers, promoting stronger molecular interactions and faster electron exchange. This work demonstrates the potential of SrTiO 3 /MXene heterostructures as a possible candidate for the reliable detection of aromatic VOCs. • SrTiO 3 , Ti 3 C 2 T x (MXene), and SrTiO 3 /Mxene were synthesized using hydrothermal approach. • The SrTiO 3 , MXene, and SrTiO 3 /MXene displayed wide, narrower, and intermediate band gaps. • SrTiO 3 /MXene displayed improved PL emission intensity due to surface defects. • SrTiO 3 /MXene displayed better sensitivity and selectivity towards toluene at 50 °C.