Plasmon-engineered anti-replacement synthesis of naked Cu nanoclusters with ultrahigh electrocatalytic activity

Anti-replacement reaction between Au nanoparticles and Cu²⁺ ions is studied under the irradiation of nanosecond laser pulses at a wavelength of 532 nm. It is revealed that high-purity naked Cu nanoclusters, which have an average diameter of 2 nm, can be extracted from CuCl₂ solution. The Au nanoparticles are also completely converted to Au³⁺ and Au⁺ ions by "hot holes". This is because of the plasmon generated "hot electrons" which overcome the limitation of thermodynamic reaction between the Au nanoparticles and Cu²⁺ ions. Furthermore, we find that the naked Cu nanoclusters exhibit enhanced electrocatalytic performance 1500 times higher than that of the ligand-protected Cu nanoclusters with similar size to achieve the oxygen reduction reaction.