| 1. |
- Fan, Lizhou, et al.
(författare)
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3D Core-Shell NiFeCr Catalyst on a Cu Nanoarray for Water Oxidation : Synergy between Structural and Electronic Modulation
- 2018
-
Ingår i: ACS Energy Letters. - : AMER CHEMICAL SOC. - 2380-8195. ; 3:12, s. 2865-2874
-
Tidskriftsartikel (refereegranskat)abstract
- Low cost transition metal-based electrocatalysts for water oxidation and understanding their structure-activity relationship are greatly desired for clean and sustainable chemical fuel production. Herein, a core-shell (CS) NiFeCr metal/metal hydroxide catalyst was fabricated on a 3D Cu nanoarray by a simple electrodeposition-activation method. A synergistic promotion effect between electronic structure modulation and nanostructure regulation was presented on a CS-NiFeCr oxygen evolution reaction (OER) catalyst: the 3D nanoarchitecture facilitates the mass transport process, the in situ formed interface metal/metal hydroxide heterojunction accelerates the electron transfer, and the electronic structure modulation by Cr incorporation improves the reaction kinetics. Benefiting from the synergy between structural and electronic modulation, the catalyst shows excellent activity toward water oxidation under alkaline conditions: overpotential of 200 mV at 10 mA/cm(2) current density and Tafel slope of 28 mV/dec. This work opens up a new window for understanding the structure-activity relationship of OER catalysts and encourages new strategies for development of more advanced OER catalysts.
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| 2. |
- Clark, Andrew G., et al.
(författare)
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Evolution of genes and genomes on the Drosophila phylogeny
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
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| 3. |
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| 4. |
- Daniel, Quentin, et al.
(författare)
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Water Oxidation Initiated by In Situ Dimerization of the Molecular Ru(pdc) Catalyst
- 2018
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Ingår i: ACS Catalysis. - : AMER CHEMICAL SOC. - 2155-5435. ; 8:5, s. 4375-4382
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Tidskriftsartikel (refereegranskat)abstract
- The mononuclear ruthenium complex [Ru(pdc)L-3] (H(2)pdc = 2,6-pyridinedicarboxylic acid, L = N-heterocycles such as 4-picoline) has previously shown promising catalytic efficiency toward water oxidation, both in homogeneous solutions and anchored on electrode surfaces. However, the detailed water oxidation mechanism catalyzed by this type of complex has remained unclear. In order to deepen understanding of this type of catalyst, in the present study, [Ru(pdc)(py)(3)] (py = pyridine) has been synthesized, and the detailed catalytic mechanism has been studied by electrochemistry, UV-vis, NMR, MS, and X-ray crystallography. Interestingly, it was found that once having reached the Ru-IV state, this complex promptly formed a stable ruthenium dimer [Ru-III(pdc)(py)(2)-O-Ru-IV(pdc)(py)(2)](+). Further investigations suggested that the present dimer, after one pyridine ligand exchange with water to form [Ru-III(pdc)(py)(2)-O-Ru-IV(pdc)(py)(H2O)](+), was the true active species to catalyze water oxidation in homogeneous solutions.
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| 5. |
- Zhang, Biaobiao, et al.
(författare)
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Defective and "c-Disordered" Hortensia-like Layered MnOx as an Efficient Electrocatalyst for Water Oxidation at Neutral pH
- 2017
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 7:9, s. 6311-6322
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Tidskriftsartikel (refereegranskat)abstract
- The development of a highly active manganese-based water oxidation catalyst in the design of an ideal artificial photosynthetic device operating under neutral pH conditions remains a great challenge, due to the instability of pivotal Mn3+ intermediates. We report here defective and "c-disordered" layered manganese oxides (MnOx-300) formed on a fluorine-doped tin oxide electrode by constant anodic potential deposition and subsequent annealing, with a catalytic onset (0.25 mA/cm(2)) at an overpotential (eta) of 280 mV and a benchmark catalytic current density of 1.0 mA/cm(2) at an overpotential (eta) of 330 mV under neutral pH (1 M potassium phosphate). Steady current density above 8.2 mA/cm(2) was obtained during the electrolysis at 1.4 V versus the normal hydrogen electrode for 20 h. Insightful studies showed that the main contributing factors for the observed high activity of MnOx-300 are (i) a defective and randomly stacked layered structure, (ii) an increased degree of Jahn-Teller distorted Mn3+ in the MnO6 octahedral sheets, (iii) effective stabilization of Mn3+, (iv) a high surface area, and (v) improved electrical conductivity. These results demonstrate that manganese oxides as structural and functional models of an oxygen-evolving complex (OEC) in photosystem II are promising catalysts for water oxidation in addition to Ni/Co-based oxides/hydroxides.
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| 6. |
- Zhang, Biaobiao, et al.
(författare)
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Electrocatalytic Water Oxidation Promoted by 3 D Nanoarchitectured Turbostratic Δ-MnOx on Carbon Nanotubes
- 2017
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Ingår i: ChemSusChem. - : Wiley-VCH Verlag. - 1864-5631 .- 1864-564X. ; 10:22, s. 4472-4478
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Tidskriftsartikel (refereegranskat)abstract
- The development of manganese-based water oxidation electrocatalysts is desirable for the production of solar fuels, as manganese is earth-abundant, inexpensive, non-toxic, and has been employed by the Photosystem II in nature for a billion years. Herein, we directly constructed a 3 D nanoarchitectured turbostratic δ-MnOx on carbon nanotube-modified nickel foam (MnOx/CNT/NF) by electrodeposition and a subsequent annealing process. The MnOx/CNT/NF electrode gives a benchmark catalytic current density (10 mA cm−2) at an overpotential (η) of 270 mV under alkaline conditions. A steady current density of 19 mA cm−2 is obtained during electrolysis at 1.53 V for 1.0 h. To the best of our knowledge, this work represents the most efficient manganese-oxide-based water oxidation electrode and demonstrates that manganese oxides, as a structural and functional model of oxygen-evolving complex (OEC) in Photosystem II, can also become comparable to those of most Ni- and Co-based catalysts.
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| 7. |
- Zhang, Peili, et al.
(författare)
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Dendritic core-shell nickel-iron-copper metal/metal oxide electrode for efficient electrocatalytic water oxidation
- 2018
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical water splitting requires efficient water oxidation catalysts to accelerate the sluggish kinetics of water oxidation reaction. Here, we report a promisingly dendritic core-shell nickel-iron-copper metal/metal oxide electrode, prepared via dealloying with an electrodeposited nickel-iron-copper alloy as a precursor, as the catalyst for water oxidation. The as-prepared core-shell nickel-iron-copper electrode is characterized with porous oxide shells and metallic cores. This tri-metal-based core-shell nickel-iron-copper electrode exhibits a remarkable activity toward water oxidation in alkaline medium with an overpotential of only 180 mV at a current density of 10 mA cm-2. The core-shell NiFeCu electrode exhibits pH-dependent oxygen evolution reaction activity on the reversible hydrogen electrode scale, suggesting that non-concerted proton-electron transfers participate in catalyzing the oxygen evolution reaction. To the best of our knowledge, the as-fabricated core-shell nickel-iron-copper is one of the most promising oxygen evolution catalysts.
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| 8. |
- Zhang, Peili, et al.
(författare)
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Gas-templating of hierarchically structured Ni-Co-P for efficient electrocatalytic hydrogen evolution
- 2017
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 5:16, s. 7564-7570
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Tidskriftsartikel (refereegranskat)abstract
- One of the grand challenges for developing scalable and sustainable hydrogen producing systems is the lack of efficient and robust earth-abundant element based catalysts for the hydrogen evolution reaction (HER). Herein, a hierarchically structured Ni-Co-P film was fabricated via a gas templating electro-deposition method. This film exhibits remarkably high catalytic performance for the HER in 1 M KOH with respective current densities of -10 and -500 mA cm(-2) at the overpotentials of -30 and -185 mV with a Tafel slope of 41 mV dec(-1). A controlled potential electrolysis experiment demonstrates that the as-prepared Ni-Co-P film is an efficient and robust catalyst with a faradaic efficiency close to 100%. Systematic characterization suggests that the unique hierarchical structure and the mutual participation of nano-sized Ni/Co based components are responsible for the high HER catalytic activity.
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| 9. |
- Zhang, Peili, et al.
(författare)
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Paired Electrocatalytic Oxygenation and Hydrogenation of Organic Substrates with Water as the Oxygen and Hydrogen Source
- 2019
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Ingår i: Angewandte Chemie International Edition. - : Wiley-VCH Verlagsgesellschaft. - 1433-7851 .- 1521-3773. ; 58:27, s. 9155-9159
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Tidskriftsartikel (refereegranskat)abstract
- The use of water as an oxygen and hydrogen source for the paired oxygenation and hydrogenation of organic substrates to produce valuable chemicals is of utmost importance as a means of establishing green chemical syntheses. Inspired by the active Ni3+ intermediates involved in electro-catalytic water oxidation by nickel-based materials, we prepared NiBx as a catalyst and used water as the oxygen source for the oxygenation of various organic compounds. NiBx was further employed as both an anode and a cathode in a paired electrosynthesis cell for the respective oxygenation and hydrogenation of organic compounds, with water as both the oxygen and hydrogen source. Conversion efficiency and selectivity of >= 99% were observed during the oxygenation of 5-hydroxy-methylfurfural to 2,5-furandicarboxylic acid and the simultaneous hydrogenation of p-nitrophenol to p-aminophenol. This paired electrosynthesis cell has also been coupled to a solar cell as a stand-alone reactor in response to sunlight.
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| 10. |
- Chen, Lin, et al.
(författare)
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A super-efficient cobalt catalyst for electrochemical hydrogen production from neutral water with 80 mV overpotential
- 2014
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 7:1, s. 329-334
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Tidskriftsartikel (refereegranskat)abstract
- Self-assembled molecular iron and cobalt catalysts (MP4N2, M = Fe, Co) bearing a multihydroxy-functionalized tetraphosphine ligand electrocatalyze H-2 generation from neutral water on a mercury electrode at -1.03 and -0.50 V vs. NHE, respectively. Complex CoP4N2 displays extremely low overpotential (E-onset = 80 mV) while maintaining high activity and good stability. Bulk electrolysis of CoP4N2 in a neutral phosphate buffer solution at -1.0 V vs. NHE produced 9.24 x 10(4) mol H-2 per mol cat. over 20 h, with a Faradaic efficiency close to 100% and without apparent deactivation.
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| 11. |
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| 12. |
- Chen, Lin, et al.
(författare)
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Tetranuclear Iron Complexes Bearing Benzenetetrathiolate Bridges as Four-Electron Transformation Templates and Their Electrocatalytic Properties for Proton Reduction
- 2013
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 52:4, s. 1798-1806
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Tidskriftsartikel (refereegranskat)abstract
- Two tetranuclear iron-sulfur complexes, (mu,mu-pbtt)[Fe-2(CO)(6)](2) (pbtt = benzene-1,2,4,5-tetrathiolato, 3) and (mu,mu-obtt)[Fe-2(CO)(6)](2) (obtt = benzene-1,2,3,4-tetrathiolato, 4), were prepared from reaction of Fe-3(CO)(12) and the corresponding tetramercaptobenzene in THF, respectively. Complexes 5 and 6, (mu,mu-pbtt)[Fe-2(CO)(5)L-1][Fe-2(CO)(5)L-2] (L-1 = CO, L-2 = PPyr(3) (Pyr = N-pyrrolyl), 5; L-1 = L-2 = PPyr(3), 6) were obtained by controlling CO displacement of 3 with PPyr(3). Molecular structures of 3-6 were determined by spectroscopic and single-crystal X-ray analyses. All-CO Fe4S4 complexes 3 and 4 each display four-electron reduction processes in consecutive chemically reversible two-electron reduction events with relatively narrow potential spans in the cyclic voltammograms. Phosphine-substituted Fe4S4 complexes 5 and 6 exhibit two consecutive two-electron reduction events, which are not fully reversible. The electrocatalytic properties of 3 and 4 for proton reduction were studied using a series of carboxylic acids of increasing strength (CH3COOH, CH2ClCOOH, CHCl2COOH, CCl3COOH, and CF3COOH). The mechanisms for electrochemical proton reduction to hydrogen catalyzed by complex 3 as a function of acid strength are discussed.
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| 13. |
- Fang, Zhiyong, et al.
(författare)
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Selective Electro-oxidation of Alcohols to the Corresponding Aldehydes in Aqueous Solution via Cu(III) Intermediates from CuO Nanorods
- 2021
-
Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:35, s. 11855-11861
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical oxidation using renewable energy is an attractive strategy that provides a sustainable and mild approach for biomass transformation. Herein, the electrocatalytic oxidation of furfuryl alcohol in an aqueous solution was investigated using CuO nanorods. Two kinds of Cu-III intermediates, namely, (CuO2)(-) and (Cu2O6)(6-), were detected on the surface of the working electrode. (Cu2O6)(6-), generated in the potential range of 1.35-1.39 V versus the reversible hydrogen electrode (RHE), induced the oxidation of furfuryl alcohol to furaldehyde with a yield of >= 98%. (CuO2)(-), generated at a potential greater than 1.39 V versus RHE, which led to the oxidation of furfuryl alcohol to 2-furoic acid with a yield of >= 99%. Furthermore, the Cu-III-catalyzed system exhibited a measure of universal applicability, wherein (Cu2O6)(6-) and (CuO2)(-) induced the highly selective electro-oxidation of benzyl alcohol, vanillyl alcohol, and 4-pyridinemethanol to yield the corresponding aldehydes and acids, respectively.
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| 14. |
- Hu, Minggang, et al.
(författare)
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Polymerization of rac-lactide catalyzed by group 4 metal complexes containing chiral N atoms
- 2012
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Ingår i: Polymer Bulletin. - : Springer Science and Business Media LLC. - 0170-0839 .- 1436-2449. ; 68:7, s. 1789-1799
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Tidskriftsartikel (refereegranskat)abstract
- The hydroxyl- and phenoxy-bridged dinuclear zirconium and hafnium complexes, 1 and 2, containing a chiral N atom in the N2O2 ligand (H2L = 2-(((2-pyridylmethyl)(2-hydroxyphenyl)amino)methyl)-4,6-di(tert-butyl)ph enol) were used as catalysts for the ring-opening polymerization of rac-lactide. Experiments prove that 1 and 2 are living and controlled catalytic systems with activity up to 3.25 g(pol) mmol(ini) (-1) h(-1). The isotactic-rich polylactides in a narrow polydispersity (M (w)/M (n) = 1.01-1.13) were produced with enantiomeric complexes 1 and 2 (P (m) = 0.65-0.73). The kinetic studies show a first-order dependency in both monomer and initiator. The initiation mechanism is discussed on the basis of the MALDI-TOF MS and H-1 NMR spectra of the rac-LA oligomer prepared by 1.
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| 15. |
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| 16. |
- Li, Fusheng, et al.
(författare)
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Dye-sensitized LaFeO3 photocathode for solar-driven H-2 generation
- 2019
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Ingår i: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 55:86, s. 12940-12943
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Tidskriftsartikel (refereegranskat)abstract
- Mesoporous LaFeO3 was used as a p-type visible-light-absorbing semiconductor (VLAS) substrate for light-driven H-2 generation. The successful modification of LaFeO3 with a molecular dye (P1*) and a molecular hydrogen production catalyst (NiP) paved a novel way to construct DS-PEC photocathodes for solar-driven H-2 generation by using VLASs.
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| 17. |
- Li, Gang, et al.
(författare)
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Selective Electrochemical Alkaline Seawater Oxidation Catalyzed by Cobalt Carbonate Hydroxide Nanorod Arrays with Sequential Proton-Electron Transfer Properties
- 2021
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:2, s. 905-913
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Tidskriftsartikel (refereegranskat)abstract
- Seawater oxygen evolution is one of the promising energy conversion technologies for large-scale renewable energy storage. It requires efficient catalysts to accelerate the oxygen evolution reaction (OER) for sustained water oxidation, avoiding chlorine evolution under acidic conditions or hypochlorite formation in alkaline solutions. Conventional metal oxide-based OER catalysts follow the adsorbate evolution mechanism that involves concerted proton-electron transfer steps at the active sites. Thus, on the scale of reversible hydrogen electrode, their catalytic activity is independent of the pH of electrolytes. In the present study, nanostructured cobalt carbonate hydroxide (CoCH) with sequential proton-electron transfer properties was tested as a catalyst for seawater oxygen evolution. CoCH exhibited pH-dependent water oxidation activities, thereby providing larger potential and current operating windows for selective water oxidation compared to the catalysts with pH-independent OER activities. The operating window can be further expanded by increasing the pH of the electrolyte.
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| 18. |
- Li, Wenlong, et al.
(författare)
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A bio-inspired coordination polymer as outstanding water oxidation catalyst via second coordination sphere engineering
- 2019
-
Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- First-row transition metal-based catalysts have been developed for the oxygen evolution reaction (OER) during the past years, however, such catalysts typically operate at overpotentials (eta) significantly above thermodynamic requirements. Here, we report an iron/ nickel terephthalate coordination polymer on nickel form (NiFeCP/NF) as catalyst for OER, in which both coordinated and uncoordinated carboxylates were maintained after electrolysis. NiFeCP/NF exhibits outstanding electro-catalytic OER activity with a low overpotential of 188 mV at 10 mA cm(-2) in 1.0 KOH, with a small Tafel slope and excellent stability. The pH-independent OER activity of NiFeCP/NF on the reversible hydrogen electrode scale suggests that a concerted proton-coupled electron transfer (c-PET) process is the rate-determining step (RDS) during water oxidation. Deuterium kinetic isotope effects, proton inventory studies and atom-proton-transfer measurements indicate that the uncoordinated carboxylates are serving as the proton transfer relays, with a similar function as amino acid residues in photosystem II (PSII), accelerating the proton-transfer rate.
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| 19. |
- Shang, Yu, et al.
(författare)
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Pyrrolic N or pyridinic N : The active center of N-doped carbon for CO2 reduction
- 2022
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Ingår i: Cuihuà xuébào. - : Elsevier BV. - 0253-9837 .- 1872-2067. ; 43:9, s. 2405-2413
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Tidskriftsartikel (refereegranskat)abstract
- Pyridinic N is widely regarded as the active center while pyrrolic N has low-activity in metal-free N-doped carbon for electrocatalytic CO2 reduction reaction (CO2RR) to CO, but this viewpoint remains open to question. In this study, through density functional theoretical calculations, we first illustrate that the intrinsic activity of pyrrolic N is high enough for effectively catalyzing CO2RR, however, due to the interplay with the neighboring pyridinic N sites, the activity of pyrrolic N is dramatically suppressed. Then, experimentally, metal-free N-doped carbon spheres (NCS) electrocatalysts without significant pyridinic N content are prepared for CO2RR. The pyrrolic N in NCS shows a direct-positive correlation with the performance for CO2RR, representing the active center with high activity. The optimum NCS could produce syngas with a wide range of CO/H-2 ratio (0.09 to 12) in CO2RR depending on the applied potential, meanwhile, the best selectivity of 71% for CO can be obtained. Intentionally adding a small amount of pyridinic N to the optimum NCS dramatically decreases the activity for CO2RR, further verifying the suppressed activity of pyrrolic N sites by the neighboring pyridinic N sites. This work reveals the interaction between a variety of N species in N-doped carbon, and the potential of pyrrolic N as the new type of active site for electrocatalysts, which can improve our understanding of the electrocatalysis mechanism and be helpful for the rational design of high-efficient electrocatalysts.
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| 20. |
- Wu, Xiujuan, et al.
(författare)
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Hierarchically Structured FeNiOxHy Electrocatalyst Formed by In Situ Transformation of Metal Phosphate for Efficient Oxygen Evolution Reaction
- 2018
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Ingår i: ChemSusChem. - : WILEY-V C H VERLAG GMBH. - 1864-5631 .- 1864-564X. ; 11:11, s. 1761-1767
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Tidskriftsartikel (refereegranskat)abstract
- A simple and low-cost fabrication method is needed to obtain effective and robust heterogeneous catalysts for the oxygen evolution reaction (OER). In this study, an electrocatalyst FeNiOxHy with a hierarchical structure is synthesized on nickel foam by a simple fabrication method through anion exchange from a metal phosphate to a metal hydroxide. The as-fabricated FeNiOxHy electrode requires overpotentials of 206 and 234 mV to deliver current densities of 10 and 50 mAcm(-2), respectively. The catalytic performance of FeNiOxHy is superior to that of most previously reported FeNi-based catalysts, including NiFe layered double hydroxide. The catalyst also shows good long-term durability at a current density of 50 mA cm(-2) over 50 h with no activity decay under 1 m KOH. By comparison to the directly electrodeposited FeNi hydroxide in morphology and electrochemical properties, the improved activity of the catalyst could be mainly attributed to an enhancement of its intrinsic activity, which was caused by the anion exchange of phosphate to (oxy)hydroxide. Further studies by cyclic voltammetry indicated a stronger interaction between Ni and Fe from the negative shift of the oxidation peak of Ni2+/Ni3+ in comparison with reported FeNiOxHy, which promoted the generation of active Ni3+ species more easily. This work may provide a new approach to the simple preparation of effective and robust OER catalysts by anion exchange.
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| 21. |
- Yang, Hao, et al.
(författare)
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Improving the performance of water splitting electrodes by composite plating with nano-SiO2
- 2018
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Ingår i: Electrochimica Acta. - : Pergamon Press. - 0013-4686 .- 1873-3859. ; 281, s. 60-68
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Tidskriftsartikel (refereegranskat)abstract
- The electrochemical splitting of water requires efficient functional electrodes. Herein, we report the fabrication of electrocatalyst consisted of an electrodeposited NiFeP alloy film which was composite plated with nano-SiO2 on nickel foam. The structure and morphology of the film were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the surface area of this NiFeP-SiO2 co-deposition alloy film can be significantly increased after electrochemical etching in a KOH solution. The water splitting properties of the alloy film were evaluated using electrochemistry. By using the NiFeP-SiO2/NF(Etched) as a bifunctional electrode, total water splitting has been demonstrated in a two-electrode cell with a current density of 10 mAcm(-2) at an applied voltage of 1.57 V, which exhibited enhanced water splitting activity in comparison to the analogue cell using the pristine NiFeP/NF electrode.
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| 22. |
- Yang, Yong, et al.
(författare)
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Evident Enhancement of Photoelectrochemical Hydrogen Production by Electroless Deposition of M-B (M = Ni, Co) Catalysts on Silicon Nanowire Arrays
- 2016
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society. - 1944-8244 .- 1944-8252. ; 8:44, s. 30143-30151
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Tidskriftsartikel (refereegranskat)abstract
- Modification of p-type Si surface by active and stable earth-abundant electrocatalysts is an effective strategy to improve the sluggish kinetics for the hydrogen evolution reaction (HER) at p-Si/electrolyte interface and to develop highly efficient and low-cost photocathodes for hydrogen production from water. To this end, Si nanowire (Si-NW) array has been loaded-with highly efficient electrocatalysts, M-B (M = Ni, Co), by facile and quick electroless plating to build M-B catalyst-modified Si nanowire-array-textured photocathodes for water reduction to H-2. Compared with the bare Si-NW array, composite Si-NWs/M-B arrays display evidently enhanced photoelectrochemical (PEC) performance. The onset potential (V-phon) of cathodic photocurrent is positively shifted by 530-540 mV to 0.44-0.45 V vs RHE, and the short-circuit current density (J(sc)) is up to 19.5 mA cm(-2) in neutral buffer solution under simulated 1 sun illumination. Impressively, the half-cell photopower conversion efficiencies (eta(hc)) of the optimized Si-NWs/Co-B (2.53%) and Si-NWs/Ni-B (2.45%) are comparable to that of Si-NWs/Pt (2.46%). In terms of the large J(sc), V-phon, and eta(hc) values, as well as the high Faradaic efficiency, Si-NW-s/M-B electrodes are among the top performing Si photocathodes which are modified with HER electrocatalysts but have no buried solid/solid junction.
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| 23. |
- Zhang, Peili, et al.
(författare)
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A Molecular Copper Catalyst for Electrochemical Water Reduction with a Large Hydrogen-Generation Rate Constant in Aqueous Solution
- 2014
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 53:50, s. 13803-13807
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Tidskriftsartikel (refereegranskat)abstract
- The copper complex [(bztpen)Cu](BF4)(2) (bztpen=N-benzyl-N,N,N-tris(pyridin-2-ylmethyl)ethylenediamine) displays high catalytic activity for electrochemical proton reduction in acidic aqueous solutions, with a calculated hydrogen-generation rate constant (k(obs)) of over 10000s(-1). A turnover frequency (TOF) of 7000h(-1)cm(-2) and a Faradaic efficiency of 96% were obtained from a controlled potential electrolysis (CPE) experiment with [(bztpen)Cu](2+) in pH2.5 buffer solution at -0.90V versus the standard hydrogen electrode (SHE) over two hours using a glassy carbon electrode. A mechanism involving two proton-coupled reduction steps was proposed for the dihydrogen generation reaction catalyzed by [(bztpen)Cu](2+).
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| 24. |
- Zhang, Peili, et al.
(författare)
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Electrocatalytic hydrogen evolution from neutral water by molecular cobalt tripyridine-diamine complexes
- 2013
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 49:82, s. 9455-9457
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Tidskriftsartikel (refereegranskat)abstract
- A cobalt complex with a tripyridine-diamine pentadentate ligand was found to be a highly active catalyst for electrochemical H-2 production from neutral water, with an activity of 860 mol H-2 (mol cat)(-1) h(-1) (cm(2) Hg)(-1) over 60 h CPE experiment at-1.25 V in a pH 7 phosphate buffer solution, without considerable deactivation.
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| 25. |
- Zhang, Peili, et al.
(författare)
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Highly efficient molecular nickel catalysts for electrochemical hydrogen production from neutral water
- 2014
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 50:91, s. 14153-14156
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Tidskriftsartikel (refereegranskat)abstract
- A series of nickel complexes containing N-5-pentadentate ligands with different amine-to-pyridine ratios were studied for electrochemical H-2 production in neutral water and the one with a diamine-tripyridine ligand displays a TON of up to 308000 over 60 h electrolysis at -1.25 V vs. SHE, with a Faradaic efficiency of similar to 91%.
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