Investigating the Effect of the Initial Valence States of Copper on CO₂ Electroreduction

: The valence states of copper always play an important role for the most studied copper‐based catalysts in CO 2 electroreduction (CO 2 ERR). In this work, distinct Cu, Cu 2 O, and CuO nanoparticles with similar particle size on active carbon are synthesized via carbonthermal reduction. Although all CuO x nanoparticles are reduced to metallic Cu during CO 2 ERR, their different initial valence states result in particle‐size variations and...