Cyclic two-step electrolysis for stable electrochemical conversion of carbon dioxide to formate.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31477719.
- Also identified by DOI 10.1038/s41467-019-11903-5 and PMC identifier 6718411.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Pd metal and Pd-based alloys are ideal catalysts that allow for the electrochemical conversion of CO<sub>2</sub> to HCOO<sup>-</sup> at almost zero-overpotential with high selectivity, but catalyst degradation caused by concurrent CO poisoning limits their practical implementation. Here, we demonstrate that cyclic two-step electrolysis, by applying the reduction and oxidation potentials alternately, achieves 100% current density stability and 97.8% selectivity toward HCOO<sup>-</sup> production for at least 45 h. The key idea for achieving the reliability is based on the selective removal of CO by controlling the parameters during the oxidation step, which utilizes the different reversibility of HCOO<sup>-</sup> and CO production reactions. Furthermore, it is found that potentiostatic electrolysis causes CO adsorption and subsequent dehydridation, which in turn lowers HCOO<sup>-</sup> selectivity. Our work provides a system-level strategy for solving the poisoning issue that is inevitable in many electrocatalytic reactions.