Accordion-like Ti3C2Tx MXene with high flexibility for NH3 sensing in self-heating mode

Abstract

Ti3C2Tx MXene was synthesized by HF (45 wt%) etching of parent Ti3AlC2 MAX phase for 7, 15, and 24 h. Microscopic studies showed that the synthesized MXenes had two-dimensional nanosheet morphology. Furthermore, compositional analyses demonstrated the existence of -F and -OH groups on Ti3C2Tx after etching. After fabrication of gas sensors, NH3 sensing at 25 °C and under 1–6 V applied voltages in self-heating condition, revealed that the Ti3C2Tx MXene sensor etched for 24 h exhibited the highest response to NH3 gas under 4 V. Furthermore, it demonstrated good flexibility on PET substrate and even after being bent 5000 times and being tilted 1000 times, its response was almost the same as its fresh state. Notably, its sensing performance at different bending angles (0–120°) was acceptable, indicating good flexibility in the bent condition. The results of this research showed the high potential of Ti3C2Tx MXene for NH3 sensing in the self-heating mode with low power consumption.