Coverage enhancement accelerates acidic CO<sub>2</sub> electrolysis at ampere-level current with high energy and carbon efficiencies.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38402216.
- Also identified by DOI 10.1038/s41467-024-45988-4 and PMC identifier 10894216.
- 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
Acidic CO<sub>2</sub> electroreduction (CO<sub>2</sub>R) using renewable electricity holds promise for high-efficiency generation of storable liquid chemicals with up to 100% CO<sub>2</sub> utilization. However, the strong parasitic hydrogen evolution reaction (HER) limits its selectivity and energy efficiency (EE), especially at ampere-level current densities. Here we present that enhancing CO<sub>2</sub>R intermediate coverage on catalysts promotes CO<sub>2</sub>R and concurrently suppresses HER. We identified and engineered robust Cu<sub>6</sub>Sn<sub>5</sub> catalysts with strong <sup>*</sup>OCHO affinity and weak <sup>*</sup>H binding, achieving 91% Faradaic efficiency (FE) for formic acid (FA) production at 1.2 A cm<sup>-2</sup> and pH 1. Notably, the single-pass carbon efficiency reaches a new benchmark of 77.4% at 0.5 A cm<sup>-2</sup> over 300 hours. In situ electrochemical Fourier-transform infrared spectroscopy revealed Cu<sub>6</sub>Sn<sub>5</sub> enhances <sup>*</sup>OCHO coverage ~2.8× compared to Sn at pH 1. Using a cation-free, solid-state-electrolyte-based membrane-electrode-assembly, we produce 0.36 M pure FA at 88% FE over 130 hours with a marked full-cell EE of 37%.