论文标题
在现实条件下的亚竞争性触发了簇中的反应性：n掺杂的案例研究（tio $ _2 $）$ _ n $用于光催化
Metastability Triggered Reactivity in Clusters at Realistic Conditions: A Case Study of N-doped (TiO$_2$)$_n$ for Photocatalysis
论文作者
论文摘要
在这里，我们报告了一种策略，即采用典型的光催化模型系统（即n掺杂（tio $ _2 $）$ _ n $簇），以准确确定可以在增强催化反应性方面起主要作用的低能能稳定结构。由于势能表面上的大量异构体，具有增强活性的特定亚稳态光催化剂的计算设计绝不是很容易的。这需要修复各种参数，即。 （i）有利的形成能，（ii）低基本间隙，（iii）低激发能和（iv）高垂直电子亲和力（VEA）和低垂直电离电位（VIP）。我们通过整合几种基于第一原则的方法来验证，仅考虑全球最低结构的考虑就可以严重低估活动。作为第一步，我们使用了一套遗传算法[Viz。使用常规的最低总能量（（ga）$ _ \ textrm {e} $）搜索群集;具有特定属性的搜索群集，即高vea（（（ga）$ _ \ textrm {p}^{\ textrm {ea}} $）和低VIP（（（ga）$ _ \ textrm {p}^{p}^{\ textrm {ip}} $ __________________________ $ __此后，我们使用从头算热力学确定了其自由能，以确认亚稳态结构距离全球最小值不远。通过分析一个大数据集，我们发现N-替代（（（n）$ _ \ textrm {o} $）更喜欢居住在高度协调的氧气位置以最大程度地提高其协调性，而n-intertitial（（no）$ _ \ _ \ textrm {o} $} $ ____________________偏爱悬挂的氧气。有趣的是，我们注意到每种类型的缺陷（即替代，间隙）大大减少了基本差距和激发能量。但是，（no）$ _ \ textrm {o} $和（n $ _2）_ \ textrm {o} $掺杂的簇是整体水分分割的潜在候选者，而n $ _ \ textrm {o} $仅对氧气进化反应而言是很美味的。
Here we report a strategy, by taking a prototypical model system for photocatalysis (viz. N-doped (TiO$_2$)$_n$ clusters), to accurately determine low energy metastable structures that can play a major role with enhanced catalytic reactivity. Computational design of specific metastable photocatalyst with enhanced activity is never been easy due to plenty of isomers on potential energy surface. This requires fixing various parameters viz. (i) favorable formation energy, (ii) low fundamental gap, (iii) low excitation energy and (iv) high vertical electron affinity (VEA) and low vertical ionization potential (VIP). We validate here by integrating several first principles based methodologies that consideration of the global minimum structure alone can severely underestimate the activity. As a first step, we have used a suite of genetic algorithms [viz. searching clusters with conventional minimum total energy ((GA)$_\textrm{E}$); searching clusters with specific property i.e. high VEA ((GA)$_\textrm{P}^{\textrm{EA}}$), and low VIP ((GA)$_\textrm{P}^{\textrm{IP}}$)] to model the N-doped (TiO$_2$)$_n$ clusters. Following this, we have identified its free energy using ab initio thermodynamics to confirm that the metastable structures are not too far from the global minima. By analyzing a large dataset, we find that N-substitution ((N)$_\textrm{O}$) prefers to reside at highly coordinated oxygen site to maximize its coordination, whereas N-interstitial ((NO)$_\textrm{O}$) and split-interstitial ((N$_2)_\textrm{O}$) favor the dangling oxygen site. Interestingly, we notice that each types of defect (viz. substitution, interstitials) reduce the fundamental gap and excitation energy substantially. However, (NO)$_\textrm{O}$ and (N$_2)_\textrm{O}$ doped clusters are the potential candidates for overall water splitting, whereas N$_\textrm{O}$ is congenial only for oxygen evolution reaction.
