Ultrathin Near-Infrared Light Activated Nano-Hotplate Catalyst

A combined photothermal-catalytic system that contains a single active element, without using different entities for separate roles (catalytic vs photothermal), is designed here for efficient catalytic reactions. Herein, ultrathin (sub-6 nm) rectangular-like KNdF₄ nanoplates consisting of 3-4 unit cell layers are prepared where the Nd³⁺ ions act as a Lewis acid catalyst. In addition, the nanoplates undergo light-to-heat conversion when irradiated with NIR light due to cross-relaxation and nonradiative relaxation processes from excited Nd³⁺ . The cyanosilylation of a series of ketones is performed using the nano-hotplate catalysts to give near quantitative yields of the cyanohydrin trimethylsilyl ethers. This is because of the high surface area-to-volume ratio of the thin nanoplates that provides a large number of surface Nd³⁺ catalytic sites for reaction. The reaction kinetics are enhanced by the photothermal effect, leading to the observed > 10-fold increase in product yields.