Exploring photoexcitation-induced dynamic evolution of the small molecule activation at point defects

Description du projet

Comment les défauts de surface affectent la performance photocatalytique

La photocatalyse, un processus qui utilise la lumière pour déclencher des réactions chimiques, est très prometteuse pour la réduction de petites molécules très stables (inertes). Les défauts ponctuels de la surface, tels que les lacunes et les hétéroatomes, contribuent à activer les molécules adsorbées durant ce processus. Avec le soutien du programme Actions Marie Skłodowska-Curie, le projet PDE SMADD entend révéler comment ces défauts évoluent et influencent l’activation des molécules sous photoexcitation. L’étude combinera des simulations avancées, notamment la théorie des perturbations à N corps et la dynamique moléculaire, avec une validation expérimentale pour explorer la manière dont les électrons excités, les transitions de spin et les effets d’exciton affectent les intermédiaires de réaction. Il examinera également comment les interfaces liquide-solide affectent l’activation. Les résultats du projet pourraient aider à relier les modèles statiques et les résultats expérimentaux, apportant une base fondamentale fiable pour améliorer l’efficacité photocatalytique.

Objectif

"For the photocatalytic reduction of inert small molecules using nanomaterials, surface point defects (such as vacancies and heteroatoms) play an important regulatory role. In particular, promoting the activation of adsorbed molecules is directly related to the subsequent multi-step reaction. Traditional simulations mainly focus on the relationship between the ground state fixation model and activation, while ignoring the exploration of the influence of dynamic evolution of defects and molecules on the activation process in the photoexcitation environment. Through the combination of first-principles, many-body perturbation theory, ab initio nonadiabatic molecular dynamics, and experimental verification, we will explore the dynamic evolution and the mechanism of the adsorbed molecule activation process at point defects under photoexcitation. 1) We will study the relaxation process of photogenerated hot electrons at point defects, analyze the formation and evolution of transient and vibrationally excited states of adsorbed molecules, and expand the static activation based on the conventional ""acceptance-donation"" mechanism. Simultaneously, by exploring the spin state transition and exciton effect at the point defects, we will reveal their effects on the lifetime of molecular dynamic activation intermediates. 2) By studying the dynamic evolution of point defects under molecular adsorption and photoexcitation, we will clarify the regulatory effect of point defects in semi-stable states on the evolution of adsorbed molecular excited states. 3) We will explore the effect of liquid-solid interfaces on the dynamic activation process of small molecules under photoexcitation. The implementation of this project will help resolve many contradictions between the static mechanism and the experimental results, and it will provide a reliable theoretical basis for the photocatalytic performance optimization of point defects."