Radical elimination forms CO, coupling with H • radical forms C1 products, and dimerization of neighboring radicals (O=C • -O-Cu) forms C2 products. The formation of C1 products requires H • radicals at this determinative step, indicating that a high proton concentration in electrolyte may be of benefit for C1 product formation due to the higher production of H • radicals. Conversely, electrolytes with low proton concentration might favor the formation of CO and C2 products as the concentration of H • radicals would be lower in such conditions.