Developing an effective catalyst to reduce carbon dioxide (CO2) to value-added C2+ products is a key challenge for CO2 utilization. Here we report a core-shell copper with native oxide (Cu@Cu2O) catalyst featuring a thin native oxide layer on the surface grown under ambient conditions. The Cu(I) oxide species on Cu@Cu2O surface remained relatively stable against reduction under CO2 electroreduction condition, and the synergism between surface Cu+ and Cu-0 in Cu@Cu2O contributed to boosting its efficiency and selectivity toward C-2 products. This Cu@Cu2O catalyst achieved an excellent selectivity (similar to 50% at -1.0 V vs reversible hydrogen electrode) for C-2 (ethylene and ethanol) production. (C) 2019 Elsevier Inc. All rights reserved.