La修饰二维Ti_(3)C_(2)T_(x)MXene的NO_(2)传感特性研究

The N0_(2) sensing characteristics of La-modified 2D Ti_(3)C_(2)T_(x) MXene

过渡金属碳氮化物Ti_(3)C_(2)T_(x)MXene具有较大的表面积、良好的导电性和丰富的表面官能团,是制作传感器的理想材料。但是纯官能团修饰的碳化钛(Ti_(3)C_(2)T_(x))响应时间不理想、稳定性差制约了其应用。采用基于密度泛函理论的第一性原理研究了La修饰二维Ti_(3)C_(2)T_(x)MXene的NO_(2)传感特性,结果表明La修饰Ti_(3)C_(2)T_(x)MXene的吸附能较未修饰前降低了20%~30%,同时吸附距离缩短,更容易转移电荷。La修饰Ti_(3)C_(2)T_(x)MXene的有效质量减小,有利于电荷转移。La修饰Ti_(3)C_(2)T_(x)的灵敏度比未修饰的灵敏度高10%~20%且衰减趋势减缓;修饰后响应和恢复时间分别缩短了10%和7%。

Transition metal carbonitride Ti_(3)C_(2)T_(x)MXene has a large specific surface area,excellent conductivity and abundant surface functional groups,making it an ideal material for sensor fabrication.Unfortunately,the undesirable response time and poor stability of pure functional group-modified Ti_(3)C_(2)T_(x)hinder its practical application.The first principle based on density functional theory was used to study the NO_(2)sensing characteristics of La-modified 2D Ti_(3)C_(2)T_(x)MXene.The results revealed that the adsorption energies of La-modified Ti_(3)C_(2)T_(x)MXene was reduced by 20%to 30%compared to that of the unmodified one,and the adsorption distance was shortened,making it easier to transfer charges.The reduction of effective mass of La-modified Ti_(3)C_(2)T_(x)MXene was beneficial for charge transfer.The sensitivity of La-modified Ti_(3)C_(2)T_(x)was 10%~20%higher than that of unmodified one,and the attenuation trend was slowed down.After modification,the response and recovery times were shortened by 10%and 7%,respectively.