scholarly journals Understanding the performance of a bisphosphonate Ru water oxidation catalyst

2020 ◽  
Vol 49 (40) ◽  
pp. 14052-14060
Author(s):  
Jesús A. Luque-Urrutia ◽  
Jayneil M. Kamdar ◽  
Douglas B. Grotjahn ◽  
Miquel Solà ◽  
Albert Poater
Keyword(s):  
Water Oxidation ◽  
Clean Energy ◽  
Oxidation Catalyst ◽  
Oxidation Catalysts

Water oxidation catalysts (WOCs) are a key part of generating H2 from water and sunlight, consequently, it is a promising process for the production of clean energy.

scholarly journals Synthesis of an amorphous Geobacter-manganese oxide biohybrid as an efficient water oxidation catalyst

2020 ◽  
Vol 22 (17) ◽  
pp. 5610-5618
Author(s):  
Shafeer Kalathil ◽  
Krishna P. Katuri ◽  
Pascal E. Saikaly
Keyword(s):  
Manganese Oxide ◽  
Water Oxidation ◽  
Geobacter Sulfurreducens ◽  
Oxidation Catalyst ◽  
Oxidation Catalysts

Self-decorated Mn2O3 nanocrystals on Geobacter sulfurreducens were synthesized as sustainable and efficient water oxidation catalysts.

(Invited) Visible Light-Driven Water Oxidation with Porphyrin Sensitizers and Water Oxidation Catalysts

2018 ◽  
Vol MA2018-01 (31) ◽  
pp. 1852-1852
Author(s):  
Hiroshi Imahori
Keyword(s):  
Excited State ◽  
Visible Light ◽  
Water Oxidation ◽  
Light Harvesting ◽  
Visible Region ◽  
Oxidation Catalyst ◽  
Efficient Production ◽  
Oxidation Catalysts ◽  
Visible Light Driven ◽  
Artificial Photosynthetic

Exporing renewable energy sources is an important task in making our society sustainable. In this regard, use of sunlight as an infinite energy source is fascinating. Specifically, realizing artificial photosynthesis, i.e., integration of light-harvesting, multi-step electron and proton transfer, and water oxidation for the efficient production of solar fuels, is a great challenge in chemistry. For the purpose, dye-sensitized photoelectrosynthesis cells (DSPSC) have been investigated, as the heterogeneous water splitting on inorganic semiconductors is promising for the upcoming large scale device operation. In DSPSC a molecular sensitizer adsorbed on a semiconducting electrode harvests visible light and injects an electron from the excited-state of the sensitizer (S*) to a conduction band (CB) of the electrode. Then, the sensitizer radical cation (S• +) extracts an electron from a water oxidation catalyst (WOC) to regenerate the sensitizer and one-electron oxidized WOC. After reiterating the cycle, high oxidation states of the WOC are produced, eventually transforming two water molecules into four protons and one oxygen molecule. As the sensitizer bis(2,2’-bipyridine)(4,4’-diphosphonato-2,2’-bipyridine)ruthenium(II) (RuP) has been frequently employed for the construction of molecule-based artificial photosynthetic systems, owing to its sufficient first oxidation potential for water oxidation and a long lifetime of its excited state for electron injection. However, the light-harvesting ability of RuP is rather low in visible region beyond 500 nm. Considering that yellow to red photons mainly shower down on the earth from sun, use of photons in visible region is essential for efficient chemical conversion by sunlight. In this context, porphyrins are attractive as the sensitizer due to their excellent light-harvesting in visible region and facile tuning of their excited-states and redox properties by their chemical functionalization. Nevertheless, molecule-based artificial photosynthetic systems with porphyrins as the sensitizer have been very limited as the result of their poor performance. One plausible reason is the occurrence of fast charge recombination (CR) between the electron injected into the CB of TiO2 (denoted as TiO2(e−)) and S• +. CR from TiO2(e−) to the oxidized WOC would also take place within a few microsecond. Undesirable CR from TiO2(e−) to water is indicated. Thus, to overcome the disadvantages, it is crucial to optimize the electron transfer (ET) processes at the interfaces. In this talk, I will give an overview of our recent initiatives on visible light-driven water oxidation with novel porphyrin sensitizers and water oxidation catalysts. [1] M. Yamamoto, L. Wang, F. Li, T. Fukushima, K. Tanaka, L. Sun and H. Imahori, Chem. Sci., 7, 1430-1439 (2016). [2] M. Yamamoto, Y. Nishizawa, P. Chábera, F. Li, T. Pascher, V. Sundström, L. Sun, and H. Imahori, Chem. Commun., 52, 13702-13705 (2016). [3] M. Yamamoto, J. Föhlinger, J. Petersson, L. Hammarström, and H. Imahori, Angew. Chem. Int. Ed., 56, 3329-3333 (2017).

scholarly journals Periodate – an alternative oxidant for testing potential water oxidation catalysts

2016 ◽  
Vol 4 (8) ◽  
pp. 2863-2872 ◽  
Author(s):  
Andrew Mills ◽  
David Hazafy ◽  
Sofia Elouali ◽  
Christopher O'Rourke
Keyword(s):  
Water Oxidation ◽  
Oxidation Catalyst ◽  
Rapid Screening ◽  
Oxidation Catalysts ◽  
Testing Potential

Periodate is used as an alternative oxidant in the rapid screening of new potential water oxidation catalyst material powders.

scholarly journals P4VP–RuII(bda) polyelectrolyte–metal complex as water oxidation catalyst: on the unique slow-diffusion and multi-charge effects of the polyelectrolyte ligand

RSC Advances ◽  
2018 ◽  
Vol 8 (68) ◽  
pp. 38818-38830 ◽  
Author(s):  
Tao Zheng ◽  
Mo Zhu ◽  
Muhammad Waqas ◽  
Ahmad Umair ◽  
Muhammad Zaheer ◽  
...  
Keyword(s):  
Metal Complex ◽  
Water Oxidation ◽  
Catalytic Mechanism ◽  
Oxidation Catalyst ◽  
Oxidation Catalysts ◽  
Charge Effects ◽  
Slow Diffusion

This work shows how the unique slow diffusion and multi-charge properties of the polyelectrolyte ligand dominate the catalytic mechanism for water oxidation catalysts.

scholarly journals Two-transition-metal water oxidation catalysts. Faster rates via electronic structure tuning

2021 ◽  
Author(s):  
Craig Hill ◽  
Meilin Tao ◽  
Qiushi Yin ◽  
Alexey Kaledin ◽  
Natalie Uhlikova ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Active Sites ◽  
Density Functional ◽  
Molecular Model ◽  
Kinetic Studies ◽  
Oxidation Catalyst ◽  
Molecular Water ◽  
Oxidation Catalysts ◽  
Order Of Magnitude ◽  
Cobalt Nickel Oxide

Abstract Mixed 3d-metal oxides are some of the most promising water oxidation catalysts (WOCs), but it is very difficult to know the active site structures and thus structure-catalytic activity correlations at the molecular level in such insoluble materials. This study reports a molecular water oxidation catalyst, [Co2Ni2(PW9O34)2]10- (Co2Ni2P2), that constitutes a molecular model of the heterogeneous WOC, cobalt-nickel oxide. Both Co2Ni2P2 and its isostructural analogue, [Co4(PW9O34)2]10- (Co4P2), have the same CoO5(H2O) active sites but Co2Ni2P2 is an order of magnitude faster than Co4P2. Co2Ni2P2 is prepared by a new synthesis, and both the location and percent occupancy of Co and Ni in Co2Ni2P2 (Co outside and Ni inside the central belt are >97% for each) is confirmed by multiwavelength synchrotron X-radiation anomalous dispersion scattering (synchrotron XRAS), a technique applied for the first time to such complexes. Density functional theory (DFT) studies predicated and reveal that Co4P2 and Co2Ni2P2 have greatly altered frontier orbitals, while stopped-flow kinetic studies and DFT calculations indicate that water oxidation by both complexes follows analogous multi-step mechanisms, including Co-OOH formation, with the energetics of most steps being lower for Co2Ni2P2 than for Co4P2.

scholarly journals A comparison of the chemical, optical and electrocatalytic properties of water-oxidation catalysts for use in integrated solar-fuel generators

2017 ◽  
Vol 10 (4) ◽  
pp. 987-1002 ◽  
Author(s):  
Ke Sun ◽  
Ivan A. Moreno-Hernandez ◽  
William C. Schmidt ◽  
Xinghao Zhou ◽  
J. Chance Crompton ◽  
...  
Keyword(s):  
Optical Properties ◽  
Water Oxidation ◽  
Oxidation Catalyst ◽  
Oxidation Catalysts ◽  
Solar Fuel ◽  
Electrocatalytic Properties ◽  
Electrocatalytic Performance

Thein situoptical properties and electrocatalytic performance of representative water-oxidation catalyst have been considered.

Revisiting Dinuclear Ruthenium Water Oxidation Catalysts: Effect of Bridging Ligand Architecture on Catalytic Activity

2021 ◽  
Vol 60 (3) ◽  
pp. 1806-1813
Author(s):  
Husain N. Kagalwala ◽  
Mahesh S. Deshmukh ◽  
Elamparuthi Ramasamy ◽  
Neelima Nair ◽  
Rongwei Zhou ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Water Oxidation ◽  
Oxidation Catalysts ◽  
Bridging Ligand ◽  
Dinuclear Ruthenium

Heterogeneous Water Oxidation Catalysts for Molecular Anodes and Photoanodes

Solar RRL ◽  
2021 ◽  
Author(s):  
Matthew V. Sheridan ◽  
Benjamin D. Sherman ◽  
Yi Xie ◽  
Ying Wang
Keyword(s):  
Water Oxidation ◽  
Oxidation Catalysts

scholarly journals Design of Molecular Water Oxidation Catalysts Stabilized by Ultrathin Inorganic Overlayers—Is Active Site Protection Necessary?

Inorganics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 105 ◽  
Author(s):  
Laurent Sévery ◽  
Sebastian Siol ◽  
S. Tilley
Keyword(s):  
Water Oxidation ◽  
Atomic Layer ◽  
Deposition Process ◽  
Operating Conditions ◽  
Molecular Water ◽  
Side Reactions ◽  
Aqueous Environment ◽  
Oxidation Catalysts ◽  
Initial Onset ◽  
Anchoring Groups

Anchored molecular catalysts provide a good step towards bridging the gap between homogeneous and heterogeneous catalysis. However, applications in an aqueous environment pose a serious challenge to anchoring groups in terms of stability. Ultrathin overlayers embedding these catalysts on the surface using atomic layer deposition (ALD) are an elegant solution to tackle the anchoring group instability. The propensity of ALD precursors to react with water leads to the question whether molecules containing aqua ligands, such as most water oxidation complexes, can be protected without side reactions and deactivation during the deposition process. We synthesized two iridium and two ruthenium-based water oxidation catalysts, which contained an aqua ligand (Ir–OH2 and Ru–OH2) or a chloride (Ir–Cl and Ru–Cl) that served as a protecting group for the former. Using a ligand exchange reaction on the anchored and partially embedded Ru–Cl, the optimal overlayer thickness was determined to be 1.6 nm. An electrochemical test of the protected catalysts on meso-ITO showed different behaviors for the Ru and the Ir catalysts. The former showed no onset difference between protected and non-protected versions, but limited stability. Ir–Cl displayed excellent stability, whilst the unprotected catalyst Ir–OH2 showed a later initial onset. Self-regeneration of the catalytic activity of Ir–OH2 under operating conditions was observed. We propose chloride ligands as generally applicable protecting groups for catalysts that are to be stabilized on surfaces using ALD.

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