Environmentally Stable, Room-Temperature NH3 Detection using PANI-Mo2TiC2 Composites toward Printable All-MXene Gas Sensors

Abstract

The detection of ammonia gas at room temperature is critical for various industrial, agricultural, and environmental applications, as ammonia poses significant risks to human health, even at low concentrations. Concurrently, there has been a rising demand for the integration of sensors onto portable and wearable devices, necessitating the development of novel, high-performance sensing materials that are printable and energy-efficient. In this study, we introduce a room-temperature ammonia gas sensor based on a polyaniline (PANI)-modified Mo₂TiC₂Tₓ (PANI-MTC) MXene composite. The PANI-MTC composite demonstrated a high gas response of 57.8% at 100 ppm and superior selectivity over other gases. Also, the addition of PANI greatly enhanced the sensor stability, where stable gas responses were observed in humid environments and during prolonged exposure to the ambient environment. Another key feature of this study is the integration of PANI-MTC and pristine MXene electrodes into a fully printable sensor design, leveraging solution-based fabrication techniques to fabricate electrodes on arbitrary substrates. Moreover, the sensor's all-MXene architecture simplifies manufacturing, enabling scalable production using cost-efficient techniques.