Controllably partial removal of thiolate ligands from unsupported Au25 nanoclusters by rapid thermal treatments for electrochemical CO2 reduction

Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands. Here, taking [Au 25 (PET) 18 ] − (PET = 2-phenylethanethiol) nanocluster as a model catalyst, this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported [Au 25 (PET) 18 ] − nanoclusters with the preservation of the core structure. This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment, avoiding the reconfiguration or agglomeration of Au 25 nanoclusters, where the degree of dethiolation can be regulated by the control of duration. This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction. Consequently, the activity and selectivity towards CO formation in electrochemical CO 2 reduction reaction of Au 25 nanoclusters can be promoted. This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.