Water Splitting-Biosynthetic System Inspired by Photosynthesis

Abstract

Harnessing sources of renewable electricity to efficiently reduce CO2 and N2 into valueadded chemicals has long been sought after as a method for clean synthesis and energy storage. In practice, these processes are limited by the lack of a high-efficiency reduction system that can operate in ambient conditions. This thesis reports several fully integrated bioelectrochemical systems designed to electrochemically split water into H2 and O2 at low driving voltages. Lithotrophic organisms facilitate the consumption of H2 and CO2 to generate biomass and chemicals at high titers and efficiencies. These scalable systems have demonstrated CO2 reduction efficiencies above 50% and can produce materials, drop-in fuels, and ammonia at ambient temperature and pressure. A maximal solar CO2 reduction efficiency of 10% is possible when coupled with photovoltaic (PV) panels of 18–20% efficiency, thereby creating a synthetic consortium comparable to the best naturally occurring photosynthetic systems.