Electrocatalysts during ethanol oxidation still suffer from poor CO₂ selectivity and are easily poisoned by CO intermediates at low overpotentials, causing great challenges for commercial viability of direct ethanol fuel cells. Herein, we report the synthesis of excavated RhNi alloy nanobranches constructed from ultrathin nanosheets with high-energy {110} facets and a large specific surface area (50.0 m² g⁻¹). These unique RhNi nanobranches achieve a CO₂ selectivity of as high as 16.0% toward the EOR in alkaline solution, far exceeding the reported value of most Pd, Pt or Rh-based electrocatalysts in alkaline solution to date. More strikingly, the excavated RhNi nanobranches show outstanding CO-poisoning tolerance ability, resulting in a high CO₂ selectivity at low potentials. Both CO stripping and in situ FTIR spectra of the EOR and CO oxidation analyses reveal that the alloying of Ni into Rh endows the nanobranches with high CO anti-poisoning ability, and thus great CO₂ selectivity at low potentials.