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Ethylene is well known as the primary product of CO₂reduction at Cu electrocatalysts using zero-gap membrane electrode assembly cells with gas diffusion cathodes. Other types of Cu electrocatalysts including oxide-derived Cu, CuSn and CuSe yield relatively more C₂oxygenates; however, the mechanisms for C₂product selectivity are not well established. This work considers selectivity trends of Cu-P_0.065, Cu-Sn_0.03, and Cu₂Se electrocatalysts made using a standard one pot synthesis method. Results show that Cu-P_0.065electrocatalysts (Cu^δ+= 0.13) retain ethylene as a primary product with relatively higher Faradaic efficiencies (FE = 43% at 350 mA cm⁻²) than undoped Cu electrocatalysts (FE = 31% at 350 mA cm⁻²) at the same current density. The primary CO₂reduction product at Cu-Sn_0.03(Cu^δ+= 0.27) electrocatalysts shifts to ethanol (FE = 48% at 350 mA cm⁻²) while CO₂reduction at Cu₂Se (Cu^δ+= 0.47) electrocatalysts favor acetate production (FE = 40% at 350 mA cm⁻²). Based on these results, we propose a common acetyl intermediate and a mechanism for selective formation of ethylene, ethanol or acetate based on the degree of partial positive charge (δ⁺) of Cu reaction sites.