Table 1.

The typical characteristics of the main redox reactions in the paired electrolysis system

	Product	Characteristics
Cathodic reactions
Group I	H2, CO, formic acid, ethylene	-High FE (>70%) -High current density (>100 mA cm−2)
Group II	Methanol, ethanol, n-propanol	-Liquid type product -Low FE (4 < x < 50 %) -Low current density (0.7 < x < 5 mA cm−2) -Laboratory scale
Group III	Methane, acetaldehyde, glyoxal, hydroxyacetone, acetone, acetate, ally alcohol, glycolaldehyde, propionaldehyde, ethylene glycola	-Lowest FE (<1%) -Lowest current density (<0.5 mA cm−2) -Laboratory scale
Anodic reactions
Group IV	Acetaldehyde, acetic acid, ethyl acetate, acrylic acid, lactic acid, formaldehyde, formic acid, glycolic acid, oxalic acid	-Cathode linked materials
Group V	2-Furoic acid, 2,5-furandicarboxylic acid	-Biomass intermediates
Group VI	Oxygen, hydrogen peroxide, benzaldehyde, benzoic acid, 4-methoxybenzaldehyde, acetophenone, acetone, phenoxyacetic acid	-Other substances

^aEthylene glycol with ionic liquid: 0.3 mA cm⁻², FE 87%⁵²