Mahabari Kajal, Mohili Ranjit D, Patel Monika, Jadhav Arvind H, Lee Kwangyeol, Chaudhari Nitin K
Advanced Hybrid Nanomaterial Laboratory, Department of Chemistry, School of Energy Technology, Pandit Deendayal Energy University Gandhinagar 382426 Gujarat India
Centre for Nano and Material Science (CNMS), Jain University Jain Global Campus Bangalore 562112 Karnataka India.
Nanoscale Adv. 2024 Aug 30;6(21):5388-97. doi: 10.1039/d4na00250d.
MXenes, characterized by their robustness, flexibility, and large surface-to-volume ratio facilitating efficient energy transfer with fast response times, have emerged as promising electrocatalysts for hydrogen generation through electrochemical water-splitting. However, the conventional synthetic route to MXenes typically involves the use of hydrofluoric acid (HF) to obtain MXenes with terminal F-functional groups. Unfortunately, these fluorine groups can negatively impact the electrocatalytic performance of MXenes. Moreover, HF is highly toxic, necessitating the development of more environmentally friendly synthetic methods. In response to these challenges, we have developed a novel HF-free microwave-assisted synthesis approach for MXenes. This method harnesses the benefits of uniform heating, homogeneous nucleation, and rapid crystal development, resulting in MXene crystallites with limited size. Importantly, our microwave-assisted approach utilizes a fluoride-free, less hazardous etchant as compared to HF for the synthesis and functionalization of MXene. The as-obtained MXene exhibits significantly improved performance towards the electrochemical hydrogen evolution reaction in alkaline media. Specifically, it demonstrates an overpotential of 140 mV at a current density of 10 mA cm and a Tafel slope of 84 mV dec. These results highlight the potential of our HF-free microwave-assisted synthesis approach for producing high-quality MXenes with enhanced electrocatalytic activity for hydrogen generation.
MXenes具有坚固性、柔韧性和大的表面积与体积比，有利于高效的能量转移且响应时间快，已成为通过电化学水分解制氢的有前景的电催化剂。然而，传统的MXenes合成路线通常涉及使用氢氟酸（HF）来获得带有末端F官能团的MXenes。不幸的是，这些氟基团会对MXenes的电催化性能产生负面影响。此外，HF毒性很强，因此需要开发更环保的合成方法。为应对这些挑战，我们开发了一种用于MXenes的新型无HF微波辅助合成方法。该方法利用了均匀加热、均匀成核和快速晶体生长的优点，得到尺寸有限大小的MXene微晶。重要的是，与HF相比，我们的微波辅助方法在MXene的合成和功能化中使用了一种无氟、危害性较小的蚀刻剂。所获得的MXene在碱性介质中对电化学析氢反应表现出显著改善的性能。具体而言，在电流密度为10 mA cm时表现出140 mV的过电位，塔菲尔斜率为84 mV dec。这些结果突出了我们的无HF微波辅助合成方法在生产具有增强的制氢电催化活性的高质量MXenes方面的潜力。
