Density functional theory calculations on single atomic catalysis:Ti-decorated Ti3C2O2 monolayer(MXene)for HCHO oxidation

Formaldehyde(HCHO) is a common indoor pollutant, long-term exposure to HCHO may harm human health. Its efficient removal at mild conditions is still challenging. The catalytic oxidation of HCHO molecules on a single atomic catalyst, Ti-decorated Ti3C2O2(Ti/Ti3C2O2) monolayer, is investigated by performing the first principles calculations in this work. It demonstrates that Ti atoms can be easily well dispersed at the form of single atom on Ti3C2O2 monolayer without aggregation. For HCHO catalytic oxidation, both Langmuir-Hinshelwood(LH) and Eley-Rideal(ER) mechanisms are considered. The results show that the step of HCHO dissociative adsorption on Ti/Ti3C2O2 with activated O2 can release high energy of 4.05 e V based on the ER mechanism, which can help to overcome the energy barrier(1.04 e V) of the subsequent reaction steps. The charge transfer from *OH group to CO molecule(dissociated from HCHO) not only promotes *OH group activation but also plays an important role in the H2 O generation along the ER mechanism. Therefore, HCHO can be oxidized easily on Ti/Ti3C2O2 monolayer, this work could provide significant guidance to develop effective non-noble metal catalysts for HCHO oxidation and broaden the applications of MXene-based materials.

刻蚀方法对Ti3C2二维材料层状结构的影响

为了进一步提高Ti3C2纳米片的层间距,分别采用HF直接刻蚀法和原位HF刻蚀法,研究了刻蚀方法对MXene(Ti3C2)层状结构的影响。结果表明,采用HF直接刻蚀法时,获得样品的形貌为风琴状多层堆叠的纳米片,当加入20 mL质量分数为30%的HF溶液,于35℃刻蚀24 h,得到层间距达1.046 nm且层状结构完整的多层Ti3C2纳米片。采用更温和的原位HF刻蚀法时,制备出更少片层的Ti3C2纳米片,层间距达到1.54 nm,层间距的增加有利于提高Ti3C2的比表面积利用率,使其在吸波材料、柔性电子元器件和传感器等领域具有潜在的应用前景。

MXene/棉织物柔性压力传感器的制备及性能研究

随着科学技术的飞速发展,柔性压力传感器在人工智能、人机交互等领域的应用越来越广泛。制备快速响应的稳定型灵敏压力传感器备受广大研究学者关注。采用简易浸涂技术,利用二维MXene表面丰富的官能团(—O,—F,—OH)与棉织物中羟基团(—OH)的界面作用,制备了导电棉织物,组装了MXene/棉织物柔性压力传感器。研究结果表明,界面作用使MXene/棉织物柔性压力传感器具有良好的稳定性,且该压力传感器具有宽传感范围(0~80 kPa)和较短的响应时间/恢复时间(53 ms/28 ms),在0~1.60 kPa压力范围内的灵敏度高达3.83 kPa;。此外,该压力传感器在人体交互方面(手指弯曲、呼吸和咽喉震动)表现出良好的监测效果,有望应用于新一代人体健康系统。