Photoinduced radical-mediated atomic dispersion of noble metal nanoparticles

The transformation of noble metal nanoparticles into atomically dispersed catalysts has been a long-standing goal to enhance metal utilization and regenerate the activity of agglomerated catalysts. Traditional methods, however, often require high temperatures, specific atmospheres, or complex chemical processes. We present a novel photoinduced strategy for atomic dispersion of noble metal nanoparticles under ambient conditions. Experimental and density functional theory calculations reveal that chlorine radicals (•Cl), together with •O₂^-, promote Pd-Pd bond cleavage. The intermediate [PdCl₄]^2- species formed adsorbs onto TiO₂ via electrostatic interactions and, upon dechlorination, stabilizes into a single-atom Pd₁-N₂O₁ structure. This method is applicable to various noble metals (Pd, Pt, Rh) and different oxide supports (TiO₂ and WO₃), and significantly enhances the catalytic activity of both commercial Pd/C and industrial waste Pd/C catalysts by 17.8-fold and 26-fold, respectively, in the hydrogenation of styrene. This approach offers a simple, green, and sustainable solution for advancing catalytic technologies.