A5010259859- Electrocatalysts for Energy Conversion
- Electrochemical Analysis and Applications
- Advanced battery technologies research
- CO2 Reduction Techniques and Catalysts
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Fuel Cells and Related Materials
- Advanced Photocatalysis Techniques
- Enzyme Catalysis and Immobilization
- Ammonia Synthesis and Nitrogen Reduction
- Microbial Fuel Cells and Bioremediation
- Machine Learning in Materials Science
- Nanocluster Synthesis and Applications
- Advanced Memory and Neural Computing
- Protein Structure and Dynamics
- Methane Hydrates and Related Phenomena
- Microbial Community Ecology and Physiology
- Biochemical and Molecular Research
- Photoreceptor and optogenetics research
- Amino Acid Enzymes and Metabolism
- Geophysical and Geoelectrical Methods
- Photosynthetic Processes and Mechanisms
- Microbial Metabolic Engineering and Bioproduction
- 2D Materials and Applications
- Pancreatic function and diabetes
RIKEN Center for Sustainable Resource Science
2017-2025
RIKEN
2025
The University of Tokyo
2014-2018
Community Catalyst
2017
Bunkyo University
2016
Understanding the competition between hydrogen evolution and CO2 reduction is of fundamental importance to increase faradaic efficiency for electrocatalytic in aqueous electrolytes. Here, by using a copper rotating disc electrode, we find that major pathway competing with water reduction, even relatively acidic electrolyte (pH 2.5). The mass-transport-limited protons takes place at potentials which there no significant reduction. This selective inhibitory effect on as well difference onset...
The Sabatier principle, which states that the binding energy between catalyst and reactant should be neither too strong nor weak, has been widely used as key criterion in designing screening electrocatalytic materials necessary to promote sustainability of our society. widespread success density functional theory (DFT) made calculations a routine practice, turning principle from an empirical into quantitative predictive tool. Given its importance electrocatalysis, we have attempted introduce...
Efficient, earth-abundant, and acid-stable catalysts for the oxygen evolution reaction (OER) are missing pieces production of hydrogen via water electrolysis. Here, we report how limitations on stability 3d-metal materials can be overcome by spectroscopic identification stable potential windows in which OER catalyzed efficiently while simultaneously suppressing deactivation pathways. We demonstrate benefits this approach using gamma manganese oxide (γ-MnO2 ), shows no signs even after 8000 h...
Hexavalent iridium (Ir
Abstract Nitrate is a pervasive aquatic contaminant of global environmental concern. In nature, the most effective nitrate reduction reaction (NRR) catalyzed by reductase enzymes at neutral pH, using highly‐conserved Mo center ligated mainly oxo and thiolate groups. Mo‐based NRR catalysts mostly function in organic solvents with low water stability. Recently, an oxo‐containing molybdenum sulfide nanoparticle that serves as catalyst pH was first reported. Herein, nanoparticle‐catalyzed system...
The binding energy between the catalyst and reactant is considered to be primary descriptor of catalytic activity. Therefore, identifying optimum that would yield maximum activity fundamentally important for development efficient catalysts. Here, we show analytically how maximizes at large reaction rates, i.e., operating conditions catalysis, may deviate from traditional understanding obtained near equilibrium. This shift can on order 0.5 eV, which easily sufficient material change....
The development of denitrification catalysts which can reduce nitrate and nitrite to dinitrogen is critical for sustaining the nitrogen cycle. However, regulating selectivity has proven be a challenge, due difficulty controlling complex multielectron/proton reactions. Here we report that utilizing sequential proton-electron transfer (SPET) pathways viable strategy enhance electrochemical an oxo-molybdenum sulfide electrocatalyst toward reduction exhibited volcano-type pH dependence with...
Abstract Elucidating the mechanism that differentiates oxygen‐evolving center of photosystem II with its inorganic counterpart is crucial to develop efficient catalysts for oxygen evolution reaction (OER). Previous studies have suggested larger overpotential MnO 2 under neutral conditions may result from instability Mn 3+ intermediate charge disproportionation. Here, by monitoring surface intermediates electrochemical OER on rutile different facet orientations, a correlation between...
Abstract Efficient, earth‐abundant, and acid‐stable catalysts for the oxygen evolution reaction (OER) are missing pieces production of hydrogen via water electrolysis. Here, we report how limitations on stability 3d‐metal materials can be overcome by spectroscopic identification stable potential windows in which OER catalyzed efficiently while simultaneously suppressing deactivation pathways. We demonstrate benefits this approach using gamma manganese oxide (γ‐MnO 2 ), shows no signs even...
A thermoneutral binding energy has been considered to yield maximum catalytic activity for decades. However, recent theoretical studies have challenged this criteria, because thermoneutrality only maximizes the near equilibrium. Here, we report experimental hydrogen of platinum be +0.094 eV, obtained by fitting microkinetic rate equations Tafel plot. Upon increasing overpotential, positive yields higher compared a catalyst. The trade-off between equilibrium and away from suggests that may...
Abstract Understanding how to tune enzymatic activity is important not only for biotechnological applications, but also elucidate the basic principles guiding design and optimization of biological systems in nature. So far, Michaelis-Menten equation has provided a fundamental framework activity. However, there still no concrete guideline on parameters should be optimized towards higher Here, we demonstrate that tuning constant ( $${K}_{m}$$ <mml:math...
The oxygen evolution reaction (OER; 2H2O → O2 + 4H+ 4e–) is being intensively studied to generate fossil fuel-independent energy carriers. As 4d/5d rare metal catalysts, such as amorphous iridium oxide (IrOx), display higher activity than 3d elucidating the critical mechanistic differences between these materials important for synthesis of cost-effective OER catalysts. Although most studies catalysts have focused on O–O bond formation energetics, here, we examined mechanism IrOx based charge...
An Ir<sup>V</sup> species with a UV-Vis absorption maximum at 450 nm mediates O–O bond formation through spin transition mechanism.
<italic>In situ</italic> electrochemical IR study of the CO<sub>2</sub> reduction by inorganic analogues carbon monoxide dehydrogenase (CODH) reveals critical role Ni in activity and selectivity Fe sulfides for reduction.
Impurity ions pose a major challenge towards diversifying water usage for electrolysis. In particular, millimolar-level chloride impurities remaining in reverse osmosis filtrates significantly diminish the selectivity and longevity of electrolyzers. Here, we show that alkali metal cations can modulate diffusion coefficient ions, enabling suppression chlorine evolution during electrolysis at diffusion-limiting conditions. Evidence cation-dependent is provided by non-zero intercepts both...
<title>Abstract</title> Impurity ions pose a major challenge towards diversifying water usage for electrolysis. In particular, millimolar-level chloride impurities remaining in reverse osmosis filtrates significantly diminish the selectivity and longevity of electrolyzers. Here, we show that alkali metal cations can regulate diffusion coefficient ions, enabling suppression chlorine evolution during electrolysis under diffusion-limiting conditions. Evidence cation dependency is provided by...
ABSTRACT Nitrogen compounds often serve as crucial electron donors and acceptors in microbial energy metabolism, playing a key role biogeochemical cycles. The energetic favorability of nitrogen oxidation–reduction (redox) reactions, driven by the thermodynamic properties these compounds, may have shaped evolution though extent their influence remains unclear. This study quantitatively evaluated similarity between energetically superior identified from 988 theoretically plausible...
<title>Abstract</title> Renewable energy sources, such as solar and wind power, fluctuate on time scales of seconds to hours. Chemical synthesis powered by these sources requires electrocatalysts that can cope with fluctuating conditions. Here, we report an electrochemical oxygen evolution reaction (OER) system is tolerant voltage fluctuations through the design catalytic pathways. By leveraging redox chemistry manganese oxide, integrated Guyard (4Mn<sup>3+</sup> + Mn<sup>7+</sup> →...
Oxygen evolution electrocatalysis has received extensive attention due to its significance in biology, chemistry, and technology. However, it is still unclear how the abundant 3d-elements can be used drive four-electron oxidation of water as efficiently Nature. In this Feature Article, we will propose a design strategy concerning optimization charge accumulation process based on our ongoing spectroelectrochemical study Mn, Fe, Ir oxygen catalysts. Spectroscopic identification reaction...
Abstract Temperature gradients are an under‐utilized source of energy with which to drive chemical reactions. Here, we review our past efforts understand how deep‐sea hydrothermal vents may harness thermal promote difficult reactions such as CO 2 reduction. Strategies amplify the driving force using temperature will be covered first, followed by a discussion on spatially separated thermodynamic can used regulate reaction selectivity. Although desirable material properties vent walls have...
The Sabatier principle states that catalytic activity can be maximized when the substrate binding affinity is neither too strong nor weak. Recent studies have shown of several hydrolases at intermediate values (Michaelis-Menten constant: K