Selective intercalation and diffusion processes in crystalline carbon nitride nanostructures

石墨碳氮化物（gCN）是一类基于sp2键C和N原子交替的低维层状化合物；它们可以被剥离成类似石墨烯的几个原子层厚的纳米结构，但具有来自杂芳香化学的额外化学功能，允许可调的带隙，嵌入化学和应用于催化和能源的关键领域。该项目的目标是开发和应用精确的电子结构计算技术来研究氮化碳材料的结构化学，以及它如何与期望的性质相关联，包括：-表面终止和控制暴露的N原子的酸/碱特征；-通过插层化学和光催化性能控制的带隙可调性；-客体原子/离子/分子在氮化碳框架中的插入和扩散机制；-与溶剂分子的表面相互作用，从而了解可能的剥离机制。该项目将广泛使用基于密度泛函理论和能量最小化技术的量子化学计算方法。机械研究的过渡态搜索将通过沿着选定的反应坐标采样系统能量来应用，例如移动物质的质心位移。适当时，从头算分子动力学（AIMD）计算也将用于检查层内和层间插入剂的迁移率。本研究的另一个目标是探索如何使用准弹性中子散射（QENS）技术来比较和合理化AIMD模拟的结果。合理理解氮化碳材料的结构-性能相关性对于优化当前性能以及为特定能源相关应用设计下一代化合物至关重要。该项目与EPSRC物理科学主题中的几个研究领域保持一致，包括能源应用材料（生长）、化学反应动力学（维持）和凝聚态物质、电子结构（维持），前者（能源应用材料）提供了最接近的匹配。

Graphitic carbon nitrides (gCN) are a family of low dimensional layered compounds based on alternating sp2-bonded C and N atoms; they can be exfoliated into few atomic layer thick nanostructures analogue to graphene, but with the additional benefit of chemical functionality derived from the heteroaromatic chemistry that allows tunable band gap, intercalation chemistry and applications in critical areas of catalysis and energy.The goal of this project is to develop and apply accurate electronic structure computational techniques to study the structural chemistry of the carbon nitride materials, and how it correlates with desired properties, including:- surface termination and control of the acid/base features of the N atoms exposed; - band gap tuneability through intercalation chemistry and control of the photocatalytic properties; - mechanism for intercalation and diffusion of guest atoms/ions/molecules in the carbon nitride framework; - surface interaction with solvent molecules leading to understanding of possible exfoliation mechanisms.The project will make extensive use of quantum chemical computational methods based on Density Functional Theory and energy minimisation techniques. Transition state searches for mechanistic studies will be applied through sampling the system energy along chosen reaction coordinates, such as the displacement of the centre of mass for mobile species. When appropriate, ab initio molecular dynamics (AIMD) calculations will also be employed to examine the mobility of intercalants within and between the layers. An additional goal of this reasearch will be to explore how results from AIMD simulations can be used to compare and rationalise experimental measurements using Quasi Elastic Neutron Scattering (QENS) techniques. Rational understanding of the structure-property correlation of the carbon nitride materials is critical for the optimisation of current properties, as well as the design of next generation compounds for specific energy related applications.The project aligns with several EPSRC research Areas within the Physical Sciences Theme, including those on Materials for energy applications (grow), Chemical reaction dynamics (maintain) and Condensed-matter, electronic structure (maintain), with the former (materials for energy application) providing the closest match.