Operando nuclear magnetic resonance decodes alkali-tuned proton-electron relay boosting CO<sub>2</sub>-to-formate conversion.
basic_science · Level V
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- Record sourced from PubMed, PMID 41554724.
- Also identified by DOI 10.1038/s41467-026-68604-z and PMC identifier 12957332.
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Abstract
The proton-coupled electron transfer (PCET) kinetics plays a critical role in governing the CO<sub>2</sub>-to-formate conversion efficiency during CO<sub>2</sub> eletroreduction reaction. While alkali metal cations are known to influence the reaction pathway, elucidating how trace doping modifies the catalytic sites remains a key challenge. Here we show that incorporating Li into bismuth oxycarbonate (BOC-Li) induces structural modifications that optimize the PCET process at bismuth-active sites, thereby boosting CO<sub>2</sub>-to-formate conversion. By employing dual-isotope (<sup>2</sup>H/<sup>13</sup>C) operando nuclear magnetic resonance (NMR) to track the formation of <sup>1</sup>H<sup>13</sup>COO<sup>-</sup>/<sup>2</sup>H<sup>13</sup>COO<sup>-</sup>, combined with kinetic isotope effect, Tafel analysis and in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy, we observe a more efficient proton-electron transfer pathway. Density functional theory (DFT) calculations suggest that Li doping is associated with enhanced activity of Bi sites, potentially strengthening H<sub>2</sub>O/CO<sub>2</sub> adsorption and reducing the O-H activation energy. Collectively, this work highlights alkali doping as a promising strategy for structurally engineering catalytic sites to improve PCET kinetics.