Multiarray Gas Sensors Using Ternary Combined Ti₃C₂T_x MXene-Based Nanocomposites

This paper reports chemiresistive multiarray gas sensors through the synthesized ternary nanocomposites, using a one-pot method to integrate two-dimensional MXene (Ti 3 C 2 T x ) with Ti-doped WO 3 (Ti-WO 3 /Ti 3 C 2 T x ) and Ti 3 C 2 T x with Pd-doped SnO 2 (Pd-SnO 2 /Ti 3 C 2 T x ). The gas sensors based on Ti-WO 3 /Ti 3 C 2 T x and Pd-SnO 2 /Ti 3 C 2 T x exhibit exceptional sensitivity, particularly in detecting 70% at 1 ppm acetone and 91.1% at 1 ppm of H 2 S. Notably, our sensors demonstrate a remarkable sensing performance in the low-ppb range for acetone and H 2 S. Specifically, the Ti-WO 3 /Ti 3 C 2 T x sensor demonstrates a detection limit of 0.035 ppb for acetone, and the Pd-SnO 2 /Ti 3 C 2 T x sensor shows 0.116 ppb for H 2 S. Simultaneous measurements with Ti-WO 3 /Ti 3 C 2 T x - and Pd-SnO 2 /Ti 3 C 2 T x -based sensors enable the evaluation of both the concentration and type of unknown target gases, such as acetone or H 2 S. Furthermore, density functional theory calculations are performed to clarify the role of Ti and Pd doping in enhancing the performance of Ti-WO 3 /Ti 3 C 2 T x and Pd-SnO 2 /Ti 3 C 2 T x nanocomposites. Theoretical simulations contribute to a deeper understanding of the doping effects, providing essential insights into the mechanisms underlying the enhanced gas response of the gas sensors. Overall, this work provides valuable insights into the gas-sensing mechanisms and introduces a novel approach for high-performance multiarray gas sensing.