Abstract Direct ethanol fuel cells have been widely investigated as nontoxic and low-corrosive energy conversion devices with high energy and power densities. It is still challenging to develop high-activity and durable catalysts for a complete ethanol oxidation reaction on the anode and accelerated oxygen reduction reaction on the cathode. The materials’ physics and chemistry at the catalytic interface play a vital role in determining the overall performance of the catalysts. Herein, we propose a Pd/Co@N-C catalyst that can be used as a model system to study the synergism and engineering at the solid-solid interface. Particularly, the transformation of amorphous carbon to highly graphitic carbon promoted by cobalt nanoparticles helps achieve the spatial confinement effect, which prevents structural degradation of the catalysts. The strong catalyst-support and electronic effects at the interface between palladium and Co@N-C endow the electron-deficient state of palladium, which enhances the electron transfer and improved activity/durability. The Pd/Co@N-C delivers a maximum power density of 438 mW cm −2 in direct ethanol fuel cells and can be operated stably for more than 1000 hours. This work presents a strategy for the ingenious catalyst structural design that will promote the development of fuel cells and other sustainable energy-related technologies.
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Surface-functionalized palladium catalysts for electrochemical CO 2 reduction
Rational design and synthesis of efficient catalysts for electrochemical CO 2 reduction is a critical step towards practical CO 2 electrolyzer systems. In this work, we report a strategy to tune the catalytic property of a metallic Pd catalyst by coating its surface with a polydiallyldimethyl ammonium (PDDA) polymer layer. The resulting PDDA-functionalized Pd/C catalysts exhibit an enhanced CO faradaic efficiency of ∼93% together with a current density of 300 mA cm −2 at −0.65 V versus reversible hydrogen electrode in comparison to non-functionalized and commercial Pd/C catalysts. X-ray photoelectron spectroscopy analysis reveals that the improvement can be attributed to the electron transfer from the quaternary ammonium groups of PDDA to Pd nanoparticles, weakening the CO binding energy on Pd. The weak CO adsorption on Pd was further confirmed by the CO temperature programmed desorption measurement and operando attenuated total reflection-Fourier-transform infrared analysis. Therefore, the incorporation of electron-donating groups could be an effective strategy to decrease the CO binding energy of a metallic catalyst for a high CO selectivity in CO 2 electroreduction.
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- Award ID(s):
- 1803200
- NSF-PAR ID:
- 10191692
- Date Published:
- Journal Name:
- Journal of Materials Chemistry A
- Volume:
- 8
- Issue:
- 31
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 15884 to 15890
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D0TA03427D
