Strategies and challenges for enhancing performance of MXene-based gas sensors: a review

With the advantages of metal conductivity, large specific surface area, and rich surface functional groups, two-dimensional (2D) MXenes have shown great potential in the field of gas sensing. However, gas sensors fabricated with pristine MXenes generally suffer from several problems such as low sensitivity, poor selectivity, significant base-resistance drift, and poor environment stability. Therefore, many efforts have been devoted to overcoming these problems. In this review, we review the progress on MXene-based gas sensors and summarize several efficient strategies (including structural design, surface modification, inorganic Schottky junction/heterojunction sensitization, polymer addition, and metal-ion intercalation) to promote the gas-sensing performance. In addition, the major challenges and future development directions of MXene-based gas sensors are also outlined in the present review. Graphical abstract