Bionic design of cytochrome c oxidase-like single-atom nanozymes for oxygen reduction reaction in enzymatic biofuel cells

Designing an artificial enzyme, from the perspective of bionics, to mimic the catalytic activity of natural enzymes is highly desirable but remains challenges. In response to the simulation of biological structure, we developed cytochrome c oxidase (CcO)-like single-atom nanozymes with FeN 5 active centers (FeN 5 SAs) in this work. Similar to the spatial structure of heme a 3 in natural CcO, the active center of FeN 5 SAs is axial N-coordinated heme-like structure and can be served as oxygen-binding site to complete oxygen reduction reaction (ORR) in respiratory electron transport chain by catalyzing the oxidation of cytochrome c (Cyt c). Depending on this bionic structure, furthermore, FeN 5 SAs exhibited competitive electrocatalytic performance towards ORR with a half-wave potential of 0.67 V (vs. RHE) at neutral condition. Coupling a glucose dehydrogenase (GDH) bioanode , the FeN 5 SAs-based glucose/O 2 enzymatic biofuel cell (EBFC) obtained a maximum power density of 149.2 ± 4.0 μW cm −2 with an open circuit potential of 0.40 ± 0.01 V. In this study, inspired by the native structure of enzymes, we develop CcO-like FeN 5 SAs and expand its application in EBFCs, which may provide an rational research approach to advance the development of nanozymes.