Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

A nitrogen-doped CuWO_₄ photoanode was synthesized by a mixed metal-imidazole casting (MiMIC) method to demonstrate the superior performance for photoelectrochemical water oxidation with IPCE of 5.6% and significant stability for 40 h.

DOI： 10.1039/d4ta04120h

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.inorgchem.3c02147

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsami.2c22483

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

A high performance for PEC water oxidation results from the formation of a p–n junction at the interface between CoPi and α-Fe₂O₃, which is first observed among the hitherto-reported α-Fe₂O₃/CoPi-based electrodes.

DOI： 10.1039/d3se00346a

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.inorgchem.2c01937

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsaem.2c00768

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsami.1c24263

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsaem.1c03379

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

Pt nanoparticles stabilized by a polymeric stabilizer of polyacrylic acid were stably adsorbed on an ITO electrode to work effectively and stably for electrocatalytic proton reduction.

DOI： 10.1039/d1se01760h

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

A Pt cathode (Pt(w-MeIm)) prepared by a mixed metal-imidazole casting (MiMIC) method showed a remarkably superior hydrogen evolution reaction (HER) performance compared to the cathode prepared without imidazole (Pt(w/o-MeIm)), and the common Pt-based benchmark cathodes of Pt/C or the Pt plate.

DOI： 10.1039/d2se00803c

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Proceedings of the National Academy of Sciences  

The understanding of O–O bond formation is of great importance for revealing the mechanism of water oxidation in photosynthesis and for developing efficient catalysts for water oxidation in artificial photosynthesis. The chemical oxidation of the Ru^II₂(OH)(OH₂) core with the vicinal OH and OH₂ ligands was spectroscopically and theoretically investigated to provide a mechanistic insight into the O–O bond formation in the core. We demonstrate O–O bond formation at the low-valent Ru^III₂(OH) core with the vicinal OH ligands to form the Ru^II₂(μ-OOH) core with a μ-OOH bridge. The O–O bond formation is induced by deprotonation of one of the OH ligands of Ru^III₂(OH)₂ via intramolecular coupling of the OH and deprotonated O⁻ ligands, conjugated with two-electron transfer from two Ru^III centers to their ligands. The intersystem crossing between singlet and triple states of Ru^II₂(μ-OOH) is easily switched by exchange of H⁺ between the μ-OOH bridge and the auxiliary backbone ligand.

DOI： 10.1073/pnas.2113910118

Scopus

PubMed

researchmap

Publishing type：Part of collection (book)   Publisher：IntechOpen  

Polypyridyl ruthenium(II) complexes have been widely researched as promising functional molecules. We have found unique photoisomerization reactions of polypyridyl ruthenium(II) aquo complexes. Recently we have attempted to provide insight into the mechanism of the photoisomerization of the complexes and distinguish between the distal−/proximal-isomers in their physicochemical properties and functions. Moreover, polypyridyl ruthenium(II) aquo complexes have been intensively studied as active water oxidation catalysts (WOCs) which are indispensable for artificial photosynthesis. The catalytic aspect and mechanism of water oxidation by the distal-/proximal-isomers of polypyridyl ruthenium(II) aquo complexes have been investigated to provide the guided thought to develop more efficient molecular catalysts for water oxidation. The recent progress on the photoisomerization and water oxidation of polypyridyl ruthenium(II) aquo complexes in our group are reviewed to understand the properties and functions of ruthenium complexes.

DOI： 10.5772/intechopen.99730

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsami.1c08949

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.electacta.2021.138545

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsaem.1c00261

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsaem.0c02628

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

The unprecedentedly low overpotential of 32 mV for oxygen evolution was attained by forming a unique motif of NiS_{<italic>x</italic>} nanowires stuffed into C₃N₄ scabbards. With this system, electrocatalytic water splitting was demonstrated at the lowest overall overpotential of 72 mV.

DOI： 10.1039/d1ee00509j

researchmap

Publishing type：Research paper (scientific journal)   Publisher：The Electrochemical Society  

DOI： 10.1149/1945-7111/abd3ba

researchmap

Other Link： https://iopscience.iop.org/article/10.1149/1945-7111/abd3ba/pdf

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsaem.0c02242

researchmap

Publishing type：Research paper (scientific journal)  

© 2020 A mononuclear Ru aquo complex, [Ru(C8Otpy)(H2dcbpy)(OH2)]2+ (C8Otpy = 4′-octyloxy-2,2′:6′,2′′-terpyridine, H2dcbpy = 4,4′-dicarboxy-2,2′-bipyridine) was stably adsorbed on a nanoporous TiO2 surface to afford a TiO2 electrode anchoring the complex. The adsorption isothermal of the complex on the TiO2 surface was analyzed by the Langmuir adsorption model to provide a maximum coverage of Гmax = 4.4 × 10−8 mol cm−2 and an adsorption equilibrium constant of Kads = 1.1 × 104 M−1, suggesting that the monolayer of the complex is formed on the TiO2 surface. The cyclic voltammetry measurement of the complex on the TiO2 surface suggested the diffusion-controlled charge transport via electron hopping between the complexes through the TiO2 layer. Pourbaix diagram showed that the complex undergoes a non-H+-coupled 1e- redox reaction of a RuIIOH/RuIIIOH pair of the complex on the TiO2 electrode due to pH buffering ability of the TiO2 surface in a range of pH 5−11. Bulk electrolysis at 1.7 V vs Ag/AgCl using the complex-anchoring TiO2 electrode provided a high and steady catalytic current density of 0.39 mA cm−2 with 83 % Faradaic efficiency for O2 evolution during 1 h electrolysis. However, we presume that the complex is transformed to RuOx nanoparticles on the TiO2 electrode during the electrocatalysis, on the basis of our earlier report on the complex / mesoporous ITO electrode system (Dalton Trans., 2020, 49, 1416−1423.). The RuOH/TiO2 electrode is the efficient anode for water oxidation under the acidic conditions, irrespective of the molecular catalyst of RuOH and the alternative catalysts formed via its oxidative transformation.

DOI： 10.1016/j.jphotochem.2020.112696

Scopus

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsaem.0c01439

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A non-heme Fe complex with a tetradentate dicarboxamide N-4 in-plane ligand works efficiently and selectively for the electrocatalytic CO2-to-CO conversion in a homogeneous DMF solution. The complex was immobilized on a nitrogen-doped graphene (N-G) to achieve a CO2-to-CO conversion in neutral aqueous NaHCO3 solutions, affording CO with Faradaic efficiency of 90%, a current density of 6 mA cm(-2), and a turnover frequency of 2.1 s(-1), at an overpotential of 0.47 V, which is among those of the hitherto-reported efficient and selective Fe complexes electrocatalysts.

DOI： 10.1021/acsaem.9b02548

Web of Science

researchmap

Language：English  

A new mononuclear Ru aquo complex [Ru(C8Otpy)(H2dcbpy)(OH2)]2+ with 4,4'-dicarboxy-2,2'-bipyridine (H2dcbpy) and 4'-octyloxy-2,2':6',2''-terpyridine (C8Otpy) ligands was synthesized to investigate electrocatalytic water oxidation by the complex immobilized on a mesoporous indium-doped tin oxide (meso-ITO) electrode using a multi-potential-step chronocoulospectrometric (MPSCCS) technique. UV-visible absorption spectroscopic data indicated that [Ru(C8Otpy)(dcbpy)(OH2)] (RuOH2) is deprotonated to [Ru(C8Otpy)(dcbpy)(OH)]- (RuOH) on the meso-ITO surface even at pH 5.9 of the electrolyte solution. The cyclic voltammogram (CV) of the RuOH/meso-ITO electrode showed a pH-independent redox response at E1/2 = 0.80 V vs. Ag/AgCl in the pH range of 5-12, being assigned to a non-proton-coupled 1e- redox process of RuIIOH/RuIIIOH. The MPSCCS measurement of the RuOH/meso-ITO electrode between 0.2 and 1.5 V vs. Ag/AgCl showed that RuIV species (tentatively RuIVO) exist in a steady state of the electrocatalysis in the initial stage. This suggests that the electrochemical oxidation from RuIVO to RuVO could compete with the water nucleophilic attack for O-O bond formation involved in the rate-determining step under the employed conditions. The possibility that the water nucleophilic attack on RuIVO could also compete with the electrochemical oxidation of RuIVO to RuVO was suggested by the electrocatalytic water oxidation at a low applied potential of 1.4 V prior to the formation potential of RuVO. The MPSCCS measurement at 1.4 V for 1 h showed that RuOH is gradually transformed into an alternative catalyst (most likely RuOx nanoparticles) on the electrode. The MPSCCS technique is promising to reveal the redox reactions and catalytic aspects of molecular catalysts immobilized on an electrode for water oxidation.

DOI： 10.1039/c9dt04442f

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Nanorod architecture of a N-2-intercalated WO3 photoanode has been developed by emphasizing the dual role of N2H4, which functioned simultaneously as a structure-directing agent and as a nitrogen source for in situ N-2 intercalation. The N content for WO3-N2H4 increased with increase of calcination temperature from 350 to 420 degrees C and thereafter decreased up to 550 degrees C. This is different from the monotonously decreased N content with the calcination temperature increase for WO3-NH3. X-ray diffraction data indicated that the phase-pure monoclinic WO3 crystals are formed over 350 degrees C calcination for WO3-N2H4, in contrast to a mixed phase of hexagonal and monoclinic WO3 crystals below 500 degrees C for WO3-NH3. The crystallinity of the monoclinic phase for WO3-N2H4 is higher than those of WO3-neat and WO3-NH3 at each calcination temperature of 350-550 degrees C. The beta values of lattice parameters of the monoclinic phase changed significantly with the calcination temperature; this is consistent with the calcination temperature dependence of the N content, clarifying the intercalation of N-2 in the WO3 lattice. The UV-visible diffuse reflectance spectra of WO3-N2H4 exhibited a shoulder at 470-630 nm, which became more intense as the calcination temperature increased from 350 degrees C and then decreased up to 550 degrees C through the maximum at 420 degrees C. This temperature dependence is consistent with the cases of the N content and the lattice parameter of beta. This indicates that N-2 intercalation into the WO3 lattice is responsible for the considerable red shift in the absorption edge, with a new shoulder appearing at 470-630 nm due to transition from a new intermediate N 2p orbital formed in the conduction band of WO3. Based on this transition, the WO3-N2H4 photoanode can utilize the visible light in longer wavelength below 520 nm for photoelectrochemical water oxidation compared to 470 nm for WO3-neat. The high incident photon-to-current conversion efficiency of the WO3-N2H4 photoanode is due to efficient electron transport through the WO3 nanorod film.

DOI： 10.1021/acssuschemeng.9b04467

Web of Science

researchmap

DOI： 10.1021/acs.inorgchem.9b01623

PubMed

researchmap

DOI： 10.1002/cssc.201802795

PubMed

researchmap

© 2019 Elsevier Inc. This review focuses on the studies of molecular water oxidation catalysts based on ruthenium, cobalt, copper, and iron, with emphasis given to the works undertaken thus far by the authors&#039; group in the last decade. A particular emphasis is given on our mechanistic studies of water oxidation, and the involvement of the chemical oxidants employed in the catalytic mechanism.

DOI： 10.1016/bs.adioch.2019.04.001

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A mu-oxido-bridged triruthenium complex (RuT2+), formed by air oxidation of a previously reported monoruthenium water-oxidation catalyst (WOC), serves as an efficient photochemical WOC with the turnover frequency (TOF) and turnover number (TON) 0.90 s(-1) and 610, respectively. The crystal structures of RuT2+ and its one-electron oxidized RuT3+ are also reported.

DOI： 10.1039/c6cc02816k

Web of Science

PubMed

researchmap

researchmap

researchmap

researchmap

Language：Japanese  

CiNii Article

CiNii Books

researchmap

Language：Japanese   Publisher：錯体化学会  

CiNii Article

researchmap

Language：Japanese   Publisher：日本工業出版  

CiNii Article

CiNii Books

researchmap