This investigation into mineral facilitated electroreduction of CO2 suggests conditions where reactions from a protometabolic Wood-Lyunghal pathway may be viable. Formic acid and acetic acid can be generated in µM quantities by the passive flow of electrons following geologically plausible pH and redox gradients established at hydrothermal vents. Additional downstream anabolic reactions (such as the conversion of fumarate to succinate) can also be carried out in the simulated hydrothermal vent. Higher temperatures lead to better conversion of CO2 to formic acid, although the reaction can still proceed under a temperature gradient analogous to extant biological systems and similar to that expected for Hadean ocean vents. Extremely small currents (nanoamps) are enough with pH and redox gradients to efficiently enable CO2 reduction. These results support the SAVT model while narrowing the search for optimal conditions for important protometabolic steps for a potential emergence of life. Our results also suggest that a variety of mineral mediators in the presence of a gradient-rich vent environment can induce two electrochemically-mediated metabolic steps for energy conversion and carbon fixation in the absence of enzymes at the interface of alkaline hydrothermal systems.