Investigation of the combination of a metal electrocatalyst (nickel nanostructures on activated carbon) with a bio-electrocatalyst (mixed anaerobic microbial consortium) for CO2 electroreduction. Biological and abiotic electrochemical experiments, in duplicate, with 3 types of electrodes: without nickel catalyst, with low nickel loading (0.01% wt.), and with high nickel loading (5% wt.). Data includes current density and charge during chronoamperometry experiments, concentration of liquid and gas compounds, optical density, NH4+ nutrient concentration, pH of catholyte, electron recovery calculations, dissolved metal concentration (measured with ICP), and microbial community composition from planktonic samples (characterized with NGS).