摘要
MXene is an emerging class of two-dimensional(2D)layered transition metal carbides or nitrides.Due to the highly tunable components and surface functional groups,it holds great potential in electrocatalytic hydrogen evolution reaction(HER).However,MXene nanosheet suffers from a strong tendency to restack and a lack of active edge sites.In this work,the porous Ti_(3)C_(2)T_(x)was synthesized by an oxidation and etching two-step strategy and then characterized by a series of spectroscopic techniques.The obtained porous Ti_(3)C_(2)T_(x)possesses a large number of in-plane pores.This not only creates abundant active edge sites but also enhances the mass transfer and increases the accessibility of the active sites.Compared with Ti_(3)C_(2)T_(x),in a 0.5 mol/L H_(2)SO_(4)electrolyte,the porous Ti_(3)C_(2)T_(x)shows a 65.6%higher electrochemical surface area(ECSA)(440 mF/cm^(2)),a 95.2%lower charge transfer resistance(12.8Ω),and a 69.8%lower Tafel slope(144 mV/dec),and thus exhibits lower overpotential with good stability at a current density of 10 mA/cm^(2).At the same time,the HER performance of the porous Ti_(3)C_(2)T_(x)can be further enhanced by near-infrared laser irradiation based on the localized surface plasmon resonance effect.
MXene是一种新兴的二维过渡金属碳化物或氮化物,具有高度可调控的组分和表面官能团,在电催化析氢反应中表现出良好的应用前景,但是MXene纳米片极易堆叠且缺乏活性边缘位点。该研究通过氧化和刻蚀两步策略合成了多孔Ti_(3)C_(2)T_(x),并采用一系列光谱学方法进行了表征。研究发现多孔Ti_(3)C_(2)T_(x)表面存在大量面内孔,这不仅增加了大量活性边缘位点,而且提高了活性位点的可及性。相比于Ti_(3)C_(2)T_(x),多孔Ti_(3)C_(2)T_(x)在0.5 mol/L H_(2)SO_(4)电解质中的电化学活性比表面积(440 mF/cm^(2))提高65.6%,电荷转移电阻(12.8Ω)降低了95.2%,塔菲尔斜率(144 mV/dec)降低了69.8%,因此在电流密度为10 mA/cm 2时表现出了更低的过电位,且具有很好的稳定性。同时,利用Ti_(3)C_(2)T_(x)的局域表面等离子体共振效应,可在近红外激光辐照下进一步提升多孔Ti_(3)C_(2)T_(x)的电催化析氢反应性能。
基金
National Outstanding Youth Science Foundation(No.52225204)。
