Parameterization and quantification of two key operando physio-chemical descriptors for water-assisted electro-catalytic organic oxidation.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39578431.
- Also identified by DOI 10.1038/s41467-024-54318-7 and PMC identifier 11584659.
- Licence recorded as CC BY-NC-ND.
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Abstract
Electro-selective-oxidation using water as a green oxygen source demonstrates promising potential towards efficient and sustainable chemical upgrading. However, surface micro-kinetics regarding co-adsorption and reaction between organic and oxygen intermediates remain unclear. Here we systematically study the electro-oxidation of aldehydes, alcohols, and amines on Co/Ni-oxyhydroxides with multiple characterizations. Utilizing Fourier transformed alternating current voltammetry (FTacV) measurements, we show the identification and quantification of two key operando parameters (ΔI<sub>harmonics</sub>/I<sub>OER</sub> and ΔV<sub>harmonics</sub>) that can be fundamentally linked to the altered surface coverage ( <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>Δ</mi> <msub><mrow><mi>θ</mi></mrow> <mrow> <msup><mrow><mi>OH</mi></mrow> <mrow><mo>*</mo></mrow> </msup> </mrow> </msub> <mo>/</mo> <msubsup><mrow><mi>θ</mi></mrow> <mrow> <msup><mrow><mi>OH</mi></mrow> <mrow><mo>*</mo></mrow> </msup> </mrow> <mrow><mi>OER</mi></mrow> </msubsup> </math> ) and the changes in adsorption energy of vital oxygenated intermediates ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <msubsup><mrow><mi>Δ</mi> <mi>G</mi></mrow> <mrow><mi>OH</mi> <mo>*</mo></mrow> <mrow><mi>EOOR</mi></mrow> </msubsup> <mo>-</mo> <msubsup><mrow><mi>Δ</mi> <mi>G</mi></mrow> <mrow><mi>OH</mi> <mo>*</mo></mrow> <mrow><mi>OER</mi></mrow> </msubsup> </math> ), under the influence of organic adsorption/oxidation. Mechanistic analysis based on these descriptors reveals distinct optimal oxyhydroxide surface states for each organics, and elucidates the critical catalyst design principles: balancing organic and M<sup>3+δ</sup>-OH* coverages and fine-tuning ΔG for key elementary steps, e.g., via precise modulation of chemical compositions, crystallinity, defects, electronic structures, and/or surface bimolecular interactions.