Wang Ying, Fu Jimin, Hu Haibo, Ho Derek
Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China.
Research Institute for Intelligent Wearable Systems, School of Fashion and Textiles, The Hong Kong Polytechnic University, Hong Kong, China.
ACS Appl Mater Interfaces. 2023 Aug 30;15(34):40846-40854. doi: 10.1021/acsami.3c08512. Epub 2023 Aug 15.
MXene exhibits numerous advantageous properties such as high electronic conductivity, high surface area, and ease of surface modification via tailoring of functional groups. However, the mechanism by which MXene functionalization enhances gas sensing performance has not yet been well understood, let alone the development of a rational sensor design optimization strategy. This work presents a functionalization methodology for MXene based on d-band center modulation, which can be implemented by introducing Fe onto the surface of TiCT nanosheets, for significantly improved gas sensing response and selectivity. The strategy is demonstrated in the design of gas sensors. The optimized gas sensor shows a response of 50% toward 10 ppm of NO at room temperature, which is over 6-fold improvement from its pristine counterpart, an unprecedented performance level among all reported MXene gas sensors. XPS characterizations, valence band analyses, and density functional theory (DFT) calculations all indicate that the underlying enhancement mechanism can be attributed to the tuning of the d-band center energy toward the Fermi level. This work provides a new design strategy based on the optimization of the d-band center energy and adds a much needed systematic and quantitative method to the design of two-dimensional materials based semiconducting gas sensors.
MXene具有许多优异的性能，如高电子导电性、高比表面积以及通过官能团定制实现表面改性的便利性。然而，MXene功能化增强气敏性能的机制尚未得到充分理解，更不用说开发合理的传感器设计优化策略了。这项工作提出了一种基于d带中心调制的MXene功能化方法，该方法可通过在TiCT纳米片表面引入铁来实现，从而显著提高气敏响应和选择性。该策略在气体传感器设计中得到了验证。优化后的气体传感器在室温下对10 ppm的NO的响应为50%，比其原始对应物提高了6倍以上，这在所有报道的MXene气体传感器中是前所未有的性能水平。X射线光电子能谱（XPS）表征、价带分析和密度泛函理论（DFT）计算均表明，潜在的增强机制可归因于d带中心能量向费米能级的调整。这项工作基于d带中心能量的优化提供了一种新的设计策略，并为二维材料基半导体气体传感器的设计增添了一种急需的系统和定量方法。
