Dual-site electrocatalysts with in situ formed metal-oxide interfaces are proposed and demonstrated to enhance the formation of multi-carbon products from electrochemical CO2reduction.The 0.5-UiO/Cu delivers a high C2+ Faradaic efficiency of over 74% with notably boosted formation rate and durability, surpassing most reported electrocatalysts.A unique mechanism of UiO-66 to induce in situ reconstruction of Cu surface and formation of UiO-66-derived amorphous ZrOx/Cu interface is uncovered, which improves the selectivity and productivity toward C2+ products.