Electrochemical conversion of CO2 to useful chemicals: current status, remaining challenges, and future opportunities

The rise of atmospheric CO2 levels must be slowed, or better reverted, to avoid further undesirable climate change. Electrochemical reduction of CO2 into value-added chemicals using renewable energy is one approach to help address this problem as it will recycle 'spent' CO2 (carbon neutral cycle) and it provides a method to store or utilize otherwise wasted excess renewable energy from intermittent sources, both reducing our dependence on fossil fuels. Current electrolysis cells accomplish either high Faradaic efficiency (often > 95% selectivity) for a desired product (e.g. CO), or reasonable current density (conversion), whereas both need to be high for a commercial process. This review will discuss current status and opportunities for catalyst design, electrolyte choice, and electrode structure.