The efficient electrochemical conversion of CO₂ to fuels or stock chemicals with high-energy density would be a major step forward in the introduction of a carbon neutral energy cycle. Especially, understanding the role of electrocatalysts, supports, and electrolytes that can efficiently reduce CO₂ to fuels with high selectivity is a subject of significant interest. Copper is the only known catalyst for producing a reasonable quantity of hydrocarbons, which means that designing proper electrode interfaces would modulate the catalytic reactivity and product selectivity. One of the observations on copper catalyst interface is that copper catalyst with a specific atomic-scale gap accelerates the reaction kinetics and selectivity to C₂₊ products, by confining CO₂ and reaction intermediates within a sub-nanoscale reactor in which the reaction energy for CO formation and subsequent C-C coupling can be accelerated. However, the selectivity control toward a target product such as ethylene or ethanol is a remaining issue to be resolved. Recently, we have designed interface rich CuO-Al₂CuO­₄ catalyst and were able to reach about 80% FE of ethylene. In-situ ATR-FTIR and DFT calculation supported that CO₂ was selectively converted to CO on CuO and subsequently CO was coupling on Al₂CuO₄ to ethylene. Therefore, designing interface rich catalysts offers efficient, yet cheap electrochemical CO₂ reduction systems.