Single Cu atom dispersed on S,N-codoped nanocarbon derived from shrimp shells for highly-efficient oxygen reduction reaction

Recently, Cu-based single-atom catalysts (SACs) have garnered increasing attention as substitutes for platinum-based catalysts in the oxygen reduction reaction (ORR). Therefore, a facile, economical, and efficient synthetic methodology for the preparation of a high-performance Cu-based SAC electrocatalyst for the ORR is extremely desired, but is also significantly challenging. In this study, we propose a ball-milling method to synthesize isolated metal SACs embedded in S,N-codoped nanocarbon (M-NSDC, M = Cu, Fe, Co, Ni, Mn, Pt, and Pd). In particular, the Cu-NSDC SACs exhibit high electrochemical activity for the ORR with half-wave potential (E_1/2) of 0.84 V (vs. reversible hydrogen electrode (RHE), 20 mV higher than Pt/C) in alkaline electrolyte, excellent stability, and electrocatalytic selectivity. Density functional theory (DFT) calculations demonstrated that the desorption of OH* intermediates was the rate-determining step over Cu-NSDC. This study creates a pathway for high-performance ORR single atomic electrocatalysts for fuel cell applications and provides opportunities to convert biowaste materials into commercial opportunities.