Atomic Surface Engineering of MXene for Stable Hydrogen Sensing at Low Temperature
Xiao Yang, Xiao Chang, Xianghong Liu, Wei Zheng, Jun Zhang
Abstract
Abstract MXenes have emerged as a promising class of two‐dimensional (2D) materials for gas sensing applications, owing to their exceptional electrical conductivity, abundant surface functional groups, and tunable surface chemistry. However, the practical implementation of MXene‐sensors is significantly hindered by the rapid oxidative degradation of their surface metallic atoms under ambient conditions. To address this challenge, an atomic‐level surface engineering strategy is developed using atomic layer deposition (ALD) to integrate ZnO and Pd onto Ti 3 C 2 T x MXene. The ZnO coating, selectively grown at hydroxyl‐rich edges/surfaces, acts as a dual‐functional layer: an ultra‐effective oxidation barrier preserving MXene's conductivity while enabling charge transport. Concurrently, Pd nanoparticles serve as highly active catalytic sites for efficient H 2 dissociation and spillover. This synergistic design yields exceptional room‐temperature hydrogen sensing performance. The optimized Pd‐ZnO/MXene sensor achieves a rapid response/recovery (23 s/64 s to 50 ppm H 2 ), outperforming most reported MXene‐based sensors. Density functional theory (DFT) confirms Pd's bifunctional catalytic role, drastically lowering energy barriers for both H 2 dissociation and O 2 adsorption/dissociation on ZnO—key to the low‐temperature activity. This ALD‐based approach establishes a universal platform for fabricating robust, high‐stability MXene sensors, advancing their real‐world deployment in hydrogen safety and clean energy applications.