Fabrication of SnO2-TiO2-Ti3C2Tx hybrids with multiple-type heterojunctions for enhanced gas sensing performance at room temperature

The development of high-performance chemiresistive gas sensors at room temperature is necessary and challenging for practical environmental monitoring and industrial production controlling. Combining MXene (two-dimensional transition metal carbide) with SMO (semiconductor metal oxide) is a promising strategy to enhance room-temperature gas sensing performance. However, there are few studies on the integration of MXene and multiphase SMO composites. Herein, we fabricate the SnO2-TiO2-Ti3C2Tx heterostructure sensor, which exhibits high sensitivity, low detection limit, excellent selectivity, and long-term stability for NO2 at 25 C. Compared with the SnO2, Ti3C2Tx, and TiO2-Ti3C2Tx sensors, the significantly improved NO2 sensing performance for the SnO2-TiO2-Ti3C2Tx sensor is attributed to the synergic effects of three phases, which not only forms functionalized surfaces for the increased gas adsorption, and more importantly, produces multiple-type heterojunctions at the SnO2/TiO2 and TiO2/Ti3C2Tx interfaces because of the suitable energy band structures among the SnO2-TiO2-Ti3C2Tx three phases, resulting in the significantly enhanced electrical transduction function for the sensor. This work sheds a new avenue to improve room-temperature gas sensing performance by coupling multiple types of heterojunctions in the SMO-MXene hybrid sensor.

Automated summary

The study focuses on the development of high-performance chemiresistive gas sensors at room temperature by combining MXene with SMO. The SnO2-TiO2-Ti3C2Tx heterostructure sensor exhibits excellent sensitivity, selectivity, and stability for NO2 detection. The improved sensing performance is attributed to the synergic effects of three phases, which form functionalized surfaces and multiple-type heterojunctions, resulting in enhanced electrical transduction function.