(a) EDX mapping images and TEM Au@Cu₂O-L NRs. (b) EDX mapping images and TEM Au@Cu₂O-M NRs. (c) EDX mapping images and TEM Au@Cu₂O-S NRs. FEs of various reduction products at different potentials tested in a flow-cell with 1.0 M KOH electrolyte for (d) Au@Cu₂O-L-10, (e) Au@Cu₂O-M-10, and (f) Au@Cu₂O-S-10 NRs, respectively. (g, h) Computed concentration distribution of CO₂ and CO species of Au@Cu₂O-L. (i, j) Computed concentration distribution of CO₂ and CO species of Au@Cu₂O-M. (k, l) Computed concentration distribution of CO₂ and CO species of Au@Cu₂O-S. (m) Schematic diagram of the cavity-confined catalytic mechanism of Au@Cu₂O-x NRs. Adapted from Ref. [31]. Copyright 2025, Springer Nature.