表面态促进的二维CuInS2介晶生长机制及光催化性能研究

二维 CuInS2（CIS）介晶兼具量子点电子结构、单晶稳定性和介孔材料大比表面，结晶有序排列单元的近场耦合增强光电性能，在有机光合成领域极具前景。高效、高选择性催化性能需基于介晶可控制备和对其结构参数与光催化性能构效关系的理解。可能影响效率和产物选择性的结构参数，如限域尺寸、裸露晶面及其结晶有序排列等均与其生长机制和动力性过程密切相关。申请人在前期的研究中发现表面态决定量子点相互作用和取向结合（OA）生长的决速步骤，表面态改变导致Ag2S量子点的相变、组装和SnO2介晶的形成。本项目拟在前期基础上，引入不同类型配体交换调节CIS二维介晶生长，研究结构单元和聚集体尺寸、结晶有序排列衍化规律并建立动力学模型拟合生长过程，结合表面状态表征和表观活化能分析揭示CIS二维介晶的形成机制和结晶有序排列的驱动力。随后，阐明二维介晶光催化醇类选择性氧化性能的构效关系，调控获得期望的高产物选择性介晶结构。

Combining the properties of aligned quantum dots (QDs) with the similar stability of single crystal and large specific surface, and allowing enhanced collective photoelectric properties by near-field coupling within ordered arrays, 2D CuInS2 (CIS) mesocrystals is the promising candidate for catalyst of organic phototransformation. To achieve structurally stable CIS with high photocatalytic efficiency and product selectivity, fundamentally, it requires the structure-controllable preparation of 2D CIS mesocrystals, and the understanding of the relationship between structure parameters and photocatalytic performance. Notably, the possible influence factor of photocatalytic performance, such as the confined size, active facet exposure prior assembly and crystallographically ordered alignment are closely related to the growth mechanisms of mesocrystals and its kinetic process. Previously, the surface states mediated oriented attachment (OA) growth or aggregation-based phase transition were investigated by candidates and co-authors. It demonstrates that the surface states determine the rate-limiting step of the OA, the change of which leads to the phase transition of amorphous MPA-capped Ag2S QDs aggregates or the formation of SnO2 mesocrytals. However, how and what time to change the surface states favors the formation of 2D mesocrystals, it needs more understanding on the growth mechanism and kinetic process of CIS mesocrystals. In this work, we aim at introducing different types of ligand exchange to tune the growth of 2D mesocrystals. The kinetic rules of QD size, aggregate or mesocrystal size and degree of crystallographically ordered alignment will be investigated and fitted by established growth model. Based on the characterization of surface states and analysis of apparent activation energy, we try to reveal the driving force of the crystallographically ordered alignment. Afterwards, efforts will be made to shed light on the relationship between the photocatalytic performance (i.e. efficiency and selectivity) and the structure parameter of 2D CIS mesocrystals. We anticipate this work could provide the fundamental understanding for kinetically changing the surface states to tune the growth of CIS, thus to tailor and achieve the desired types of mesocrystals with high photocatalytic efficiency and product selectivity.