Limits...
Electrodeposition of hierarchically structured three-dimensional nickel-iron electrodes for efficient oxygen evolution at high current densities.

Lu X, Zhao C - Nat Commun (2015)

Bottom Line: Here we show that an efficient oxygen electrode can be developed by electrodepositing amorphous mesoporous nickel-iron composite nanosheets directly onto macroporous nickel foam substrates.The as-prepared oxygen electrode exhibits high catalytic activity towards water oxidation in alkaline solutions, which only requires an overpotential of 200 mV to initiate the reaction, and is capable of delivering current densities of 500 and 1,000 mA cm(-2) at overpotentials of 240 and 270 mV, respectively.The electrode also shows prolonged stability against bulk water electrolysis at large current.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry, The University of New South Wales, Sydney, New South Wales 2052, Australia.

ABSTRACT
Large-scale industrial application of electrolytic splitting of water has called for the development of oxygen evolution electrodes that are inexpensive, robust and can deliver large current density (>500 mA cm(-2)) at low applied potentials. Here we show that an efficient oxygen electrode can be developed by electrodepositing amorphous mesoporous nickel-iron composite nanosheets directly onto macroporous nickel foam substrates. The as-prepared oxygen electrode exhibits high catalytic activity towards water oxidation in alkaline solutions, which only requires an overpotential of 200 mV to initiate the reaction, and is capable of delivering current densities of 500 and 1,000 mA cm(-2) at overpotentials of 240 and 270 mV, respectively. The electrode also shows prolonged stability against bulk water electrolysis at large current. Collectively, the as-prepared three-dimensional structured electrode is the most efficient oxygen evolution electrode in alkaline electrolytes reported to the best of our knowledge, and can potentially be applied for industrial scale water electrolysis.

No MeSH data available.


XRD patterns of as-prepared and annealed NiFe/NF samples.The pentagram and triangle represent the Bragg reflections for hematite1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4382694&req=5

f2: XRD patterns of as-prepared and annealed NiFe/NF samples.The pentagram and triangle represent the Bragg reflections for hematite1.

Mentions: Supplementary Fig. 4 shows the elemental distributions of Ni and Fe in the NiFe/NF composite detected by energy-dispersive X-ray spectroscopy. The Ni and Fe are indexed with red and green colour in the energy-dispersive X-ray spectroscopy images, respectively. Both Ni and Fe are found to distribute uniformly in the whole area tested, confirming the deposition of homogeneous NiFe bimetallic composites over the NF substrate. The XRD pattern shown in Fig. 2 exhibits only three diffraction peaks of the NF at 44.5°, 51.8° and 76.4°, respectively34, without the detection of any new diffraction peaks, further confirming that the NiFe deposited onto NF is amorphous in nature. Post-annealing treatment will endow NiFe/NF crystallinity. Also shown in Fig. 2, at the annealing temperature (Tanneal) ≥500 °C, new diffraction peaks at 36.5° and 63.5° are emerged, ascribed to the crystalline hematite structure1. However, the OER catalytic activity of NiFe/NF decreases accordingly with the increased Tanneal (Supplementary Fig. 5), indicating that the amorphous structures of NiFe composite are more active for OER. This result is in accordance with that observed by Smith et al.1, and could possibly be ascribed to the larger surface area and higher electrical conductivity that are offered by amorphous phase materials31.


Electrodeposition of hierarchically structured three-dimensional nickel-iron electrodes for efficient oxygen evolution at high current densities.

Lu X, Zhao C - Nat Commun (2015)

XRD patterns of as-prepared and annealed NiFe/NF samples.The pentagram and triangle represent the Bragg reflections for hematite1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4382694&req=5

f2: XRD patterns of as-prepared and annealed NiFe/NF samples.The pentagram and triangle represent the Bragg reflections for hematite1.
Mentions: Supplementary Fig. 4 shows the elemental distributions of Ni and Fe in the NiFe/NF composite detected by energy-dispersive X-ray spectroscopy. The Ni and Fe are indexed with red and green colour in the energy-dispersive X-ray spectroscopy images, respectively. Both Ni and Fe are found to distribute uniformly in the whole area tested, confirming the deposition of homogeneous NiFe bimetallic composites over the NF substrate. The XRD pattern shown in Fig. 2 exhibits only three diffraction peaks of the NF at 44.5°, 51.8° and 76.4°, respectively34, without the detection of any new diffraction peaks, further confirming that the NiFe deposited onto NF is amorphous in nature. Post-annealing treatment will endow NiFe/NF crystallinity. Also shown in Fig. 2, at the annealing temperature (Tanneal) ≥500 °C, new diffraction peaks at 36.5° and 63.5° are emerged, ascribed to the crystalline hematite structure1. However, the OER catalytic activity of NiFe/NF decreases accordingly with the increased Tanneal (Supplementary Fig. 5), indicating that the amorphous structures of NiFe composite are more active for OER. This result is in accordance with that observed by Smith et al.1, and could possibly be ascribed to the larger surface area and higher electrical conductivity that are offered by amorphous phase materials31.

Bottom Line: Here we show that an efficient oxygen electrode can be developed by electrodepositing amorphous mesoporous nickel-iron composite nanosheets directly onto macroporous nickel foam substrates.The as-prepared oxygen electrode exhibits high catalytic activity towards water oxidation in alkaline solutions, which only requires an overpotential of 200 mV to initiate the reaction, and is capable of delivering current densities of 500 and 1,000 mA cm(-2) at overpotentials of 240 and 270 mV, respectively.The electrode also shows prolonged stability against bulk water electrolysis at large current.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry, The University of New South Wales, Sydney, New South Wales 2052, Australia.

ABSTRACT
Large-scale industrial application of electrolytic splitting of water has called for the development of oxygen evolution electrodes that are inexpensive, robust and can deliver large current density (>500 mA cm(-2)) at low applied potentials. Here we show that an efficient oxygen electrode can be developed by electrodepositing amorphous mesoporous nickel-iron composite nanosheets directly onto macroporous nickel foam substrates. The as-prepared oxygen electrode exhibits high catalytic activity towards water oxidation in alkaline solutions, which only requires an overpotential of 200 mV to initiate the reaction, and is capable of delivering current densities of 500 and 1,000 mA cm(-2) at overpotentials of 240 and 270 mV, respectively. The electrode also shows prolonged stability against bulk water electrolysis at large current. Collectively, the as-prepared three-dimensional structured electrode is the most efficient oxygen evolution electrode in alkaline electrolytes reported to the best of our knowledge, and can potentially be applied for industrial scale water electrolysis.

No MeSH data available.