Areti Moutsiou, Andrea Olivati, Luis A. Cipriano, Alessandra Sivo, Sean M. Collins, Quentin M. Ramasse, Ik Seon Kwon, Giovanni Di Liberto, Mohamad Kanso, Robert Wojcieszak, Gianfranco Pacchioni, Annamaria Petrozza, Gianvito Vilé
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引用次数: 0
Abstract
Understanding charge transfer in light-driven processes is crucial for optimizing the efficiency and performance of a photocatalyst, as charge transfer directly influences the separation and migration of photogenerated charge carriers and determines the overall reaction rate and product formation. However, achieving this understanding remains challenging in the context of single-atom photocatalysis. This study addresses this gap and investigates an Ag-based single-atom catalyst (Ag1@CNx) in the photocatalytic oxidation of benzyl alcohol to benzaldehyde. Comprehensive characterization was conducted using a battery of diffractive, textural, spectroscopic, and microscopic methods, confirming the catalyst crystallinity, porosity, elemental composition, and atomic dispersion of silver atoms. This material displayed efficient performance in the selective oxidation of benzyl alcohol to benzaldehyde. Density functional theory calculations were used to rationalize the catalyst structure and elucidate the reaction mechanism, unveiling the role of the photogenerated holes in lowering the reaction energy barriers. Time-resolved transient spectroscopic studies were used to monitor the dynamics of photogenerated charges in the reaction, revealing the lifetimes and behaviors of excited states within the catalyst. Specifically, the introduction of silver atoms led to a significant enhancement in the excited state lifetime, which favors the hole-transfer in the presence of the benzyl alcohol. This indicated that the photoexcited carriers were effectively transferred to the reactant, thereby driving the oxidation process in the presence of oxygen. These mechanistic insights are pivotal in spectroscopically elucidating the reaction mechanism and can be practically applied to design single-atom photocatalysts more rationally, targeting materials that combine both rapid reductive quenching and efficient charge transfer to the metal.
期刊介绍:
ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels.
The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.