Au25 Nanoclusters Exhibit Superhigh Catalytic Activity in Electrochemical Detection of As(III)

An atomic-level Au nanocluster, as an excellent photocatalyst, is generally not considered as an efficient electrocatalyst due to its poor stability. Herein, a method is proposed to stabilize abundant Au-25 on Fe2O3 nanoplates (Au-25/OV-Fe2O3) successfully with oxygen vacancies (OV) created. Au-25/OV-Fe2O3 shows superhigh catalysis in the electrochemical reduction toward As(III). The record-breaking sensitivity (161.42 mu A ppb(-1)) is two orders of magnitude higher than currently reported, where an ultratrace limit of detection (9 ppt) is obtained, suggesting promising applications in the analysis of organic and bioactive substances. The stability of Au-25 is attributed to the Au-Fe bond formed after loading Au-25 nanoclusters on Fe2O3 nanoplates through electron compensation and bond length (Au-S) shortening. Moreover, the ligand S atoms in Au-25 nanoclusters significantly contribute to the reduction of As(III). The fantastic stability and superior catalytic ability of Au-25/OV-Fe2O3 provide guidelines to stabilize Au nanoclusters on metal oxides, indicating their potential electroanalytical applications.

Automated summary

The study successfully stabilizes Au-25 nanoclusters on Fe2O3 nanoplates, forming Au-25/OV-Fe2O3 with superhigh electrochemical reduction catalytic activity, breaking sensitivity records and offering promising applications in the analysis of organic and bioactive substances. The Au-Fe bond and S atoms in Au-25 nanoclusters play important roles in the reduction of As(III). The fantastic stability and catalytic ability of Au-25/OV-Fe2O3 provide guidelines for stabilizing Au nanoclusters on metal oxides.