Single palladium atoms stabilized by β-FeOOH nanorod with superior performance for selective hydrogenation of cinnamaldehyde

Atomically dispersed single atom catalysts represent an ideal means of converting less valuable organics into value-added chemicals of interest with high efficiency. Herein, we describe a facile synthetic approach to create defect-containing β-FeOOH doped with isolated palladium atoms that bond covalently to the nearby oxygen and iron atoms. The presence of singly dispersed palladium atoms is confirmed by spherical aberration correction electron microscopy and extended X-ray absorption fine structure measurements. This single palladium atom catalyst manifests outstanding catalytic efficiency (conversion: 99%; selectivity 99%; turnover frequency: 2,440 h⁻¹) in the selective hydrogenation of cinnamaldehyde to afford hydrocinnamaldehyde. Experimental measurements and density functional theory (DFT) calculations elucidate the high catalytic activity and the strong metal-support interaction stem from the unique coordination environment of the isolated palladium atoms. These findings may pave the way for the facile construction of single atom catalysts in a defect-mediated strategy for efficient organic transformations in heterogeneous catalysis.