Deepak Namitha, Jain Vanshika, Pillai Pramod P
Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, India.
Photochem Photobiol. 2024 Jul-Aug;100(4):1000-1009. doi: 10.1111/php.13937. Epub 2024 Mar 14.
Photocatalysis with plasmonic nanoparticles (NPs) is emerging as an attractive strategy to make and break chemical bonds. However, the fast relaxation dynamics of the photoexcited charge carriers in plasmonic NPs often result in poor yields. The separation and extraction of photoexcited hot-charge carriers should be faster than the thermalization process to overcome the limitation of poor yield. This demands the integration of rationally chosen materials to construct hybrid plasmonic photocatalysts. In this work, the enhanced photocatalytic activity of gold nanoparticle-titanium dioxide metal-semiconductor heterostructure (Au-TiO) is used for the efficient regeneration of nicotinamide (NADH) cofactors. The modification of plasmonic AuNPs with n-type TiO semiconductor enhanced the charge separation process, because of the Schottky barrier formed at the Au-TiO heterojunction. This led to a 12-fold increment in the photocatalytic activity of plasmonic AuNP in regenerating NADH cofactor. Detailed mechanistic studies revealed that Au-TiO hybrid photocatalyst followed a less-explored light-independent pathway, in comparison to the conventional light-dependent path followed by sole AuNP photocatalyst. NADH regeneration yield reached ~70% in the light-independent pathway, under optimized conditions. Thus, our study emphasizes the rational choice of components in hybrid nanostructures in dictating the photocatalytic activity and the underlying reaction mechanism in plasmon-powered chemical transformations.
等离子体纳米颗粒（NPs）光催化正成为一种制造和断裂化学键的有吸引力的策略。然而，等离子体纳米颗粒中光激发电荷载流子的快速弛豫动力学常常导致产率低下。光激发热载流子的分离和提取应比热化过程更快，以克服产率低的限制。这就需要整合合理选择的材料来构建混合等离子体光催化剂。在这项工作中，金纳米颗粒-二氧化钛金属-半导体异质结构（Au-TiO）增强的光催化活性被用于烟酰胺（NADH）辅因子的高效再生。用n型TiO半导体修饰等离子体金纳米颗粒增强了电荷分离过程，这是由于在Au-TiO异质结处形成了肖特基势垒。这使得等离子体金纳米颗粒在再生NADH辅因子时的光催化活性提高了12倍。详细的机理研究表明，与单一金纳米颗粒光催化剂遵循的传统光依赖途径相比，Au-TiO混合光催化剂遵循的是一条较少被探索的光不依赖途径。在优化条件下，光不依赖途径中的NADH再生产率达到了约70%。因此，我们的研究强调了在混合纳米结构中合理选择组分对决定光催化活性和等离子体驱动化学转化中潜在反应机制的重要性。
