TiO $_2$电化学界面的表面化学与双电层耦合
Coupling of surface chemistry and electric double layer at TiO$_2$ electrochemical interfaces
摘要：
在工作条件下，金属氧化物的表面通常由于酸碱化学而带电。用抗衡离子补偿的带电界面形成所谓的双电层。表面化学和双电层的耦合被认为是至关重要的，但由于缺乏原子尺度的信息，人们对其了解甚少。本文采用基于密度泛函理论的有限场分子动力学模拟方法研究了金红石型TiO $_2$（110）-NaCl电解质界面的亥姆霍兹电容随pH值的变化规律。研究发现，由于表面吸附和双电层的竞争力，水分子在高pH值下具有更强的结构波动，从而导致更大的电容。还可以看出，在低pH下的界面质子转移显著增加电容值。这些发现阐明了滴定实验中观察到的相同趋势的微观起源。
英文摘要：
Surfaces of metal oxides at working conditions are usually electrified due to the acid-base chemistry. The charged interface compensated with counterions forms the so-called electric double layer. The coupling of surface chemistry and electric double layer is considered to be crucial but poorly understood because of lacking the information at the atomistic scale. Here, we used the latest development in density functional theory based finite-field molecular dynamics simulation to investigate pH-dependence of the Helmholtz capacitance at electrified rutile TiO$_2$ (110)-NaCl electrolyte interfaces. It is found that, due to competing forces from surface adsorption and from electric double layer, water molecules have a stronger structural fluctuation at high pH and this leads to a much larger capacitance. It is also seen that, interfacial proton transfers at low pH increase significantly the capacitance value. These findings elucidate the microscopic origin for the same trend observed in titration experiments.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
