Engineering High-Performance Gas Sensors via MXene-Driven Synergistic Perovskite Heterostructures

Abstract

MXene (Ti3C2Tx) has emerged as a highly promising functional material, offering high conductivity, hydrophilic surface terminations, and a large surface-to-volume ratio, facilitating rapid charge transport and abundant active sites, which makes them ideal for real-time sensing applications. Despite these advantages, Ti3C2Tx nanosheets naturally restack through van der Waals interactions. This structural collapse reduces the accessible surface area and limits gas adsorption efficiency, ultimately hindering its standalone sensing performance.1 Overcoming this limitation is essential to unlock its full potential as a sensor. To achieve this, alkaline-earth-metal-based perovskites have been incorporated, as they offer structural flexibility, thermal stability, tunable oxygen vacancies, and strong metal-oxygen bonding characteristics.2 These perovskites boost the surface reactivity and promote effective modulation of charge carriers during gas adsorption. In particular, SrTiO3, SrFeO3, and SrZrO3 provide stable frameworks and abundant oxygen defect sites that strengthen gas-surface interactions. These perovskites, when integrated with Ti3C2Tx, prevent MXene restacking by acting as spacers. This facilitates efficient charge transfer, significantly improving sensitivity, selectivity, and response-recovery dynamics.3 These synergistic perovskite-MXene hybrids enable real-time, room temperature detection of hazardous gases and biomarkers. Specifically, the SrTiO3-MXene heterostructure sensor yields a 38.79% response to 50 ppm NO2 gas, and the SrFeO3-MXene sensor detected 250 ppb acetone with a 20.5% response. Tailoring perovskite morphology maximizes sensor performance by enhancing interfacial contact with the MXene sheets. In this case, the cube-shaped SrZrO3-MXene sensor achieved 32% response to 5000 ppm methane. These results highlight the efficiency of the nanocomposites towards real-time monitoring of the gases at ambient temperature.