| 1. |
- Chen, C., et al.
(författare)
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Boosting Electrocatalytic Water Oxidation by Creating Defects and Lattice-Oxygen Active Sites on Ni-Fe Nanosheets
- 2020
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Ingår i: ChemSusChem. - : Wiley-VCH Verlag. - 1864-5631 .- 1864-564X. ; 13:18, s. 5067-5072
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Tidskriftsartikel (refereegranskat)abstract
- Layered nickel-iron oxide/hydroxide nanosheets have proven to be the most efficient catalyst for the water oxidation reaction. Introducing structural defects to the nanosheets is a particularly attractive method for increasing the number of active sites and tailoring the intrinsic electronic properties. Herein, defects were introduced on Ni−Fe nanosheets through sequentially electrodoping and dedoping the surface of the material with tetramethylammonium ions. The as-prepared defect-rich Ni−Fe nanosheets showed an enhanced catalytic performance for the oxygen evolution reaction (OER) compared with conventional NiFe layered double hydroxides (LDHs), exhibiting an overpotential of only 172 mV at the current density of 10 mA cm−2. The relationship between pH and OER activity indicated that the lattice oxygens participated in the catalytic OER process as active sites. This work provides new insights into the understanding of the structure-activity relationship of layered materials and helps to develop new methods to implement defects on such frameworks aided by organic molecules.
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| 2. |
- Lee, H., et al.
(författare)
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Homogeneous Electrochemical Water Oxidation at Neutral pH by Water-Soluble NiII Complexes Bearing Redox Non-innocent Tetraamido Macrocyclic Ligands
- 2020
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Ingår i: ChemSusChem. - : Wiley-VCH Verlag. - 1864-5631 .- 1864-564X.
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Tidskriftsartikel (refereegranskat)abstract
- Water oxidation is the bottleneck reaction in artificial photosynthesis. Exploring highly active and stable molecular water oxidation catalysts (WOCs) is still a great challenge. In this study, a water-soluble NiII complex bearing a redox non-innocent tetraamido macrocyclic ligand (TAML) is found to be an efficient electrocatalyst for water oxidation in neutral potassium phosphate buffer. Controlled-potential electrolysis experiments show that it can sustain at a steady current of approximately 0.2 mA cm−2 for >7 h at 1.75 V versus normal hydrogen electrode (NHE) without the formation of NiOx. Electrochemical and spectroelectrochemical tests show that the redox-active ligand, as well as HPO4 2− in the buffer, participate in the catalytic cycle. More importantly, catalytically active intermediate [NiIII(TAML2−)−O.] is formed via several proton-coupled electron transfer processes and reacts with H2O with the assistance of base to release molecular oxygen. Thus, the employment of redox non-innocent ligands is a useful strategy for designing effective molecular WOCs.
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| 3. |
- Lee, H., et al.
(författare)
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Ligand-Controlled Electrodeposition of Highly Intrinsically Active and Optically Transparent NiFeOxHy Film as a Water Oxidation Electrocatalyst
- 2017
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Ingår i: ChemSusChem. - : Wiley-VCH Verlag. - 1864-5631 .- 1864-564X. ; 10:23, s. 4690-4694
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Tidskriftsartikel (refereegranskat)abstract
- A highly intrinsically active and optically transparent NiFeOxHy water oxidation catalyst was prepared by electrodeposition of [Ni(C12-tpen)](ClO4)2 complex (Ni−C12). This NiFeOxHy film has a current density of 10 mA cm−2 with an overpotential (η) of only 298 mV at nanomolar concentration and the current density of 10 mA cm−2 remains constant over 22 h in 1 m KOH. The extremely high turnover frequency of 0.51 s−1 was obtained with η of 300 mV. More importantly, such outstanding activity and transparency (optical loss <0.5 %) of the NiFeOxHy film are attributed to a ligand effect of the dodecyl substituent in Ni−C12, which enables its future application in solar water splitting.
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| 4. |
- Zhang, P., et al.
(författare)
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NiIII-rich NiFeBa as an Efficient Catalyst for Water Oxidation
- 2021
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Ingår i: ChemSusChem. - : John Wiley and Sons Inc. - 1864-5631 .- 1864-564X. ; 14:12, s. 2516-2520
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Tidskriftsartikel (refereegranskat)abstract
- Electrocatalytic water oxidation requires efficient catalysts to reduce the overpotential and accelerate the sluggish kinetics of oxygen formation. Here, a promising NiFeBa material was prepared by the co-electrodeposition of Ba2+, Ni2+, and Fe3+ as an efficient catalyst for electrocatalytic water oxidation. NiFeBa showed enhanced water oxidation performance compared with NiFe layered double hydroxide and NiFe oxide, delivering a current density of 10 mA cm−2 at an overpotential of 180 mV. Doped Ba ions played a key role in stabilizing the electrogenerated Ni3+ species, producing more octahedral Ni−O structures for lattice oxygen-based water oxidation, adjusting the catalytic mechanism, and finally leading to an enhancement of catalytic efficiency.
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