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Abstract Aldehyde‐assisted water electrolysis offers an attractive pathway for energy‐saving bipolar hydrogen production with combined faradaic efficiency (FE) of 200% while converting formaldehyde into value‐added formate. Herein we report the design and synthesis of noble metal‐free Cu6Sn5alloy as a highly effective electrocatalyst for formaldehyde electro‐oxidative dehydrogenation, demonstrating a geometric current density of 915 ± 46 mA cm−2at 0.4 V versus reversible hydrogen electrode, outperforming many noble metal electrocatalysts reported previously. The formaldehyde‐assisted water electrolyzer delivers 100 mA cm−2at a low cell voltage of 0.124 V, and a current density of 486 ± 20 mA cm−2at a cell voltage of 0.6 V without any iR compensation and exhibits nearly 200% faradaic efficiency for bipolar hydrogen production at 100 mA cm−2in 88 h long‐term operation. Density functional theory calculations further confirm the notably lowered barriers for dehydrogenation and Tafel steps on the Cu₆Sn₅ surface compared to Cu, underscoring its potential as a highly active catalyst.
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This content will become publicly available on April 28, 2026
Revealing Coexisting Cu 0 –Cu + Sites in Cu 3 N Nanoensembles for Selective CC Coupling of CO 2 Under Low Overpotential
To address a long‐existing debate on what copper species are responsible for efficient CC coupling, especially ethanol formation, in electrochemical CO2reduction reaction, herein, a comprehensive study using Cu3N nanocubes with a uniform size and shape, alongside a single crystalline phase is reported. The Cu3N nanoensemble electrode has a remarkable Faradaic efficiency (FE) of 64% for ethanol production at a relatively low potential of −0.6 V versus reversible hydrogen electrode. Throughin‐operandoX‐ray absorption spectroscopy study, a dynamic phase evolution that directly correlates with changes in FE across varying applied potentials is observed. Notably, the nanoensemble with a composition of ≈71% Cu+and 29% Cu0is identified as being selective for ethanol formation at the low overpotential. Conversely, a predominantly metallic Cu phase formed at potentials more negative than −0.6 V favors the hydrogen evolution reaction. Density functional theory calculations at the Cu3N–Cu interface substantiate that the coexistence of Cu0–Cu+not only energetically favors the ethanol reaction pathway but also destabilizes the intermediates for ethylene pathway.
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- Award ID(s):
- 2400385
- PAR ID:
- 10642588
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemSusChem
- Volume:
- 18
- Issue:
- 15
- ISSN:
- 1864-5631
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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