Hierarchical Modulation in Cu‐Aerogel Enables Breakthrough CO 2 Electroreduction for Combating Stability‐Efficiency‐Selectivity Tradeoff

protective layer for high stability, the body assembled Boron improves the binding affinity to intermediates and shifts Cu d-band upward for enhanced charge transfer. BSnCu3 achieves exceptional performance, including an ethanol selectivity of 93.2%, a Faradaic efficiency (FE) of 90.3%, and an ultralow overpotential of 0.12 V, alongside remarkable stability. Leveraging the synergistic effects of regionally assembled Boron/Tin and the efficient charge/mass transfer of the 3D nanowire network, BSnCu3 attains a record-breaking tradeoff index of 2.74, surpassing all reported values. This work presents an inspiring strategy and sets a new benchmark for advanced electrocatalyst design.