纳米合金结构与电催化脱卤活性的理论研究

The nano-alloy has superior electrochemical catalytic activity of dehalogenation of halohydrocarbon, which makes it popular in the electrochemical treatment of water pollution. It is important to improve the electrochemical properties such as current density and current efficiency by tuning the alloy structure and reducing the activation energy of electrochemical dehalogenation. The composition, segregation and morphology of the nano-alloys have great influence on the experimental and theoretical results, so it is crucial to establish a reasonable model to study the catalytic activity of the nano-alloy. Compared with other methods, Monte Carlo method based on empirical potential has advantages in the space and time scales which makes it become an efficient method for simulating large catalyst nanoparticles. In this project, we will apply the Monte Carlo simulation method with the newly developed the coordination-dependent interatomic interaction and construct the reasonable structure of nano-alloy. We will study the dehalogenation of alkyl halides and aromatic halides on the surfaces of nanoalloys by the means of theoretical chemistry and investigate the elemental effect and alloy structure which are beneficial to improve the catalytic activity. This study will not only be used to improve the electrochemical efficiency of dehalogenation, but also develop methods that can be helpful to other researchers in exploring the interface properties of nano-metal.

纳米合金具有电催化卤代烃脱卤活性，有望在电化学水体污染治理技术中得到推广应用。通过调控合金结构降低电化学脱卤活化能，对于提高电流密度、电流效率等电化学性质至为重要。纳米合金的组成、偏析与形貌对实验与理论研究结果影响极大，因此建立合理的纳米合金合金模型是探讨催化性能的必要前提。与其它方法相比，基于经验势的蒙特卡洛方法具有空间、时间尺度上的优势，为模拟大尺度金属催化剂纳米颗粒提供了高效方法。本项目基于新发展的适用于金属纳米颗粒的原子相互作用势模型，应用蒙特卡洛模拟方法，建立合理的纳米合金结构模型；通过理论化学手段研究卤代烷烃、卤代芳烃在纳米合金表面的电催化脱卤过程，探索有利于提高催化活性的元素效应与合金结构，并期望在实践中予以验证。本项目研究结果不仅可以应用于提高电催化脱卤效率，所发展的相关方法也可被其他探索纳米金属表界面性质的研究所借鉴。

纳米合金因具有电催化卤代烃脱卤活性，在电化学水体污染治理技术中得到应用。为降低电化学脱卤活化能，提高交换电流密度、电流效率等电化学性质，本项目围绕卤素在纳米电极表面的电催化过程，开展了电极合金结构的相关模拟与计算，建立了卤素电化学催化的动力学方程与活性模型，用分子动力学理论模拟方法探索了过渡态。根据我们的理论和方法得到的结果，我们提出用双描述符定位电催化活性催化剂的理论方法，给出了金属电极电催化脱卤的活性火山图。这对构建催化剂活性图谱，研发高电化学活性水体污染物降解电极材料具有普遍意义。本项目提出的理论与方法基于电化学的基本原理，因此适用于大多数电催化反应，对电催化材料的理性设计与大通量筛选具有科学意义。