Boosting oxygen reduction activity on silver nanocluster via selectively exposure of solvent coordinated sites

Abstract

Metal nanoclusters (MNCs) have sparked extensive research interest in catalysis. However, addressing the spatial resistance induced by the surface ligands and the high aggregation tendency of the MNCs is challenging during the catalytic process. In this work, we presented a rational strategy to expose the metal sites occupied by weak coordination, thereby activating the catalytic centers. Specially, the Ag12 nanoclusters containing six acetonitrile auxiliary ligands was prepared (AgNCs) and the solvent molecules was removed through mild photo-reduction. Meanwhile, graphene oxide (GO) was introduced as supports to stabilize the AgNCs for further control of the geometrical structure while modulate the coordination and electronic environment. According to the theoretic density functional theory (DFT) calculations, compared with the bulk AgNCs, the free Ag atoms without CH3CN enhanced the interactions with the intermediates of *OOH, pointing to promising catalytic ability for oxygen reduction reaction (ORR). The activated AgNCs@GO exhibited a half-wave potential of 915 mV vs. RHE and low Tafel slope of 45 mV dec-1 for ORR. This work developed the method to boost the catalytic activity of MNCs towards electrochemical scenario, demonstrating the promising potential of MNCs-based materials for electrocatalysis.