STEP, Efficient solar syntheses: A comprehensive approach to decreasing the concentration of atmospheric carbon dioxide

J. Lau, S. Licht, J. Stuart, F-F Li, F. Meng
George Washington University, US

Keywords: solar synthesis, sustainability, climate change, green chemistry

Summary:

The Solar Thermal Electrochemical Process (STEP) was introduced to provide a complete solution to lowering carbon dioxide in the atmosphere (1). STEP utilizes a synergy of thermal and electrochemical energy to drive endothermic processes at increased efficiencies and high rates. STEP is a versatile technique that applies thermal energy to concentrated reactants to decrease the energy of endothermic electrolysis reactions. By elevating reactant temperature using solar thermal energy, the voltage needed to drive the endothermic electrolysis reactions can be tuned to allow for sub-bandgap sunlight that was previously discarded by photovoltaics1 This process has been shown experimentally for processes ranging from the initial water splitting experiment to bleach production, iron metal production, cement, and carbon dioxide reduction. STEP can achieve in excess of 50% solar energy conversion efficiency. Utilizing different molten salt mediums, these processes have been shown to occur at very low energy and to maintain current densities (A cm-2) sustaining high process rates. STEP utilizes chemical and solar thermal concentrations to adjust the tuning potentials of endothermic electrolysis processes to allow more efficient conversions. 1. STEP: A solar chemical process to end anthroprogenic global warming. J. Phys. Chem. C, 113, 16283, 2009.