Hydroxide promotes carbon dioxide electroreduction to ethanol on copper via tuning of adsorbed hydrogen.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31862886.
- Also identified by DOI 10.1038/s41467-019-13833-8 and PMC identifier 6925210.
- 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
Producing liquid fuels such as ethanol from CO<sub>2</sub>, H<sub>2</sub>O, and renewable electricity offers a route to store sustainable energy. The search for efficient electrocatalysts for the CO<sub>2</sub> reduction reaction relies on tuning the adsorption strength of carbonaceous intermediates. Here, we report a complementary approach in which we utilize hydroxide and oxide doping of a catalyst surface to tune the adsorbed hydrogen on Cu. Density functional theory studies indicate that this doping accelerates water dissociation and changes the hydrogen adsorption energy on Cu. We synthesize and investigate a suite of metal-hydroxide-interface-doped-Cu catalysts, and find that the most efficient, Ce(OH)<sub>x</sub>-doped-Cu, exhibits an ethanol Faradaic efficiency of 43% and a partial current density of 128 mA cm<sup>-2</sup>. Mechanistic studies, wherein we combine investigation of hydrogen evolution performance with the results of operando Raman spectroscopy, show that adsorbed hydrogen hydrogenates surface *HCCOH, a key intermediate whose fate determines branching to ethanol versus ethylene.