Department of Physics, Barkatullah University, Bhopal-462026, India.
Phys Chem Chem Phys. 2019 Feb 20;21(8):4633-4640. doi: 10.1039/c8cp07038e.
Using first principles density functional theory, we have studied the interaction mechanism of NO2 and SO2 gas molecules on an MoB2 monolayer, for gas sensing applications. The selectivity for a particular gas by the sensor has been analyzed through electronic structure calculations and adsorption studies. The calculations have been performed by considering the fact that the MoB2 monolayer as a sensing material encounters a change in its electrical properties, when gas molecules with different orientations get adsorbed on the surface. From the density of states study, we find better selectivity for NO2 as compared to SO2, as the latter leaves the electronic structure of the sensing material unaffected. Further, the adsorption curves support the above fact as the larger value of adsorption energy (Ead ∼ -1 eV) for NO2 indicates stronger adsorption. The chemisorptive nature for NO2, in contrast with the relatively weaker physisorption for SO2, additionally supports the fact that NO2 gas has a better perspective for MoB2 sensor application. Charge density plots for each case are in good agreement with the above conclusions. The faster recovery time attributes the MoB2 monolayer better as a sensor material for NO2 interaction.
利用第一性原理密度泛函理论，我们研究了 NO2 和 SO2 气体分子在 MoB2 单层上的相互作用机制，用于气体传感应用。通过电子结构计算和吸附研究分析了传感器对特定气体的选择性。在考虑到 MoB2 单层作为传感材料的情况下，当具有不同取向的气体分子吸附在表面上时，其电性质会发生变化，因此进行了计算。从态密度研究中，我们发现与 SO2 相比，NO2 具有更好的选择性，因为后者不会改变传感材料的电子结构。此外，吸附曲线支持了上述事实，因为 NO2 的吸附能（Ead∼-1 eV）较大，表明吸附更强。与 SO2 相对较弱的物理吸附相比，NO2 的化学吸附特性进一步支持了这样一个事实，即 NO2 气体对 MoB2 传感器应用具有更好的前景。每个案例的电荷密度图都与上述结论一致。更快的恢复时间使 MoB2 单层更适合作为 NO2 相互作用的传感器材料。
