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Abstract The broad employment of water electrolysis for hydrogen (H2) production is restricted by its large voltage requirement and low energy conversion efficiency because of the sluggish oxygen evolution reaction (OER). Herein, we report a strategy to replace OER with a thermodynamically more favorable reaction, the partial oxidation of formaldehyde to formate under alkaline conditions, using a Cu3Ag7electrocatalyst. Such a strategy not only produces more valuable anodic product than O2but also releases H2at the anode with a small voltage input. Density functional theory studies indicate the H2C(OH)O intermediate from formaldehyde hydration can be better stabilized on Cu3Ag7than on Cu or Ag, leading to a lower C-H cleavage barrier. A two-electrode electrolyzer employing an electrocatalyst of Cu3Ag7(+)||Ni3N/Ni(–) can produce H2at both anode and cathode simultaneously with an apparent 200% Faradaic efficiency, reaching a current density of 500 mA/cm2with a cell voltage of only 0.60 V.
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Cage Effect of Nitrogen Oxide Radicals Enables Li‐NO x Cell with a 3.8 V Cell Voltage
Abstract The utilization of redox‐active gas as cathode materials has been proposed as a promising approach to meet the demand for next‐generation battery technologies. Toward this end, nitrogen oxides (NOx)—inexpensive, abundant gases readily produced from ammonia on an industrial scale—is a promising energy storage media; however, its utilization as cathode material has not been achieved. In this work, the cage effect of NO and NO2radicals are utilized to stabilize the charge product of Li‐NOxcell as N2O3. This cell operates via reversible redox of LiNO3to N2O3, achieving a specific capacity of 1,570 mA h gcarbon−1or 25 mA h cmelectrode−2 at a full cell voltage of 3.85 V with an average energy efficiency of 89% at a current density up to 2 mA cmelectrode−2. These metrics represent one of the highest areal capacity, current density, cell voltage, and energy efficiency reported for a metal‐gas cells.
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- PAR ID:
- 10640388
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 37
- Issue:
- 43
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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