@article{Cai2025, 
author = {Yang Cai and Jinlong Xiong and Yuwei Wang and Hafiz Muhammad Adeel Sharif and Jiahao Cai and Ting Pan and Xueren Tan and Zhuo Li and Changping Li},
title = {Single-atom Pd confined in Ti3C2 nanosheet for boosted room-temperature trace NO2 monitoring},
year = {2025},
journal = {Nano Research},
volume = {18},
number = {4},
pages = {94907285},
keywords = {Ti3C2 MXene, sensing mechanism, NO2 sensor, Pd single atom, in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)},
url = {https://www.sciopen.com/article/10.26599/NR.2025.94907285},
doi = {10.26599/NR.2025.94907285},
abstract = {Two-dimensional MXenes have great potential for gas sensing applications due to their distinct electronic structure and unique surface properties. However, low sensitivity and poor selectivity to target gas at room temperature are major shortcomings of MXene materials. In this study, PdCl2 was used to decorate Pd single atoms (PdSA) on Ti3C2 nanosheet (Ti3C2/PdSA). The Pd2+ was directly reduced (in-situ) into a PdSA due to abundant Ti vacancies and the inherent reducing ability of Ti3C2 MXene. The Ti3C2/PdSA sensor exhibited the highest response of 0.289 to 1 ppm NO2, which is 28.9 and 7.8 times higher over pristine Ti3C2 and Pd nanoparticles (Pdnano)-decorated on Ti3C2 (Ti3C2/Pdnano), respectively. Simultaneously, the Ti3C2/PdSA sensor possessed an ultralow detection limit (10 ppb) and excellent selectivity towards NO2. The enhanced gas sensing mechanism of Ti3C2/PdSA was investigated in detail through the activation energy calculation, in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and density functional theory (DFT) studies. The rich active sites, chemical sensitization effect, and NO2 adsorption enhancement resulting from the Pd single atoms in Ti3C2/PdSA significantly boosted sensing performance. This work can provide new insights and guidelines for fabricating highly effective NO2 sensors operated at room temperature.}
}