We have found that copper(II) ions at about equimolar Cu2+/photosystem II (PS II) reaction center proportions stimulate oxygen evolution nearly twofold. This high affinity Cu-binding site is different from the binding sites of Mn and Ca ions. The analysis of the Cu2+ content in PS II preparations isolated from wild-type tobacco and a tobacco mutant deficient in light-harvesting complex suggests that Cu2+ may be a native component of PS II and may take part in the oxygen evolution process. At higher concentrations, Cu2+ ions inhibit oxygen evolution and quench fluorescence.
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http://dx.doi.org/10.1515/znc-2002-9-1016 | DOI Listing |
ACS Appl Mater Interfaces
December 2024
TCS Research, Sahyadri Park 2, Rajiv Gandhi Infotech Park, Hinjewadi Phase 3, Pune 411057, India.
Realization of a sustainable hydrogen economy in the future requires the development of efficient and cost-effective catalysts for its production at scale. MXenes (MX) are a class of 2D materials with 'n' layers of carbon or nitrogen (X) interleaved by 'n+1' layers of transition metal (M) and have emerged as promising materials for various applications including catalysts for hydrogen evolution reaction (HER). Their properties are intimately related to both their composition and their atomic structure.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Shenzhen University, Chemistry, Nanhai Ave 3688, 518060, Shenzhen, CHINA.
The high entropy alloy (HEA) possesses distinctive thermal stability and electronic characteristics, which exhibits substantial potential for diverse applications in electrocatalytic reactions. However, accurately controlling the size of HEA still remains a challenge, especially for the ultrasmall HEA nanoparticles. Herein, we firstly calculate and illustrate the size impact on the electronic structure of HEA and the adsorption energies of crucial intermediates in typical electrocatalytic reactions, such as the hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), CO2 electroreduction (CO2RR) and NO3- electroreduction (NO3RR).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
University of Science and Technology of China, Hefei National Research Center for Physical Sciences at Microscale, jinzhai road, hefei, CHINA.
Herein, we first report a photocatalytic OCM using CO2 as a soft oxidant for C2H6 production under mild conditions, where an efficient photocatalyst with unique interface sites is constructed to facilitate CO2 adsorption and activation, while concurrently boosting CH4 dissociation. As a prototype, the Au quantum dots anchored on oxygen-deficient TiO2 nanosheets are fabricated, where the Au-Vo-Ti interface sites for CO2 adsorption and activation are collectively disclosed by in situ Kelvin probe force microscopy, quasi in situ X-ray photoelectron spectroscopy and theoretical calculations. Compared with single metal site, the Au-Vo-Ti interface sites exhibit the lower CO2 adsorption energy and decrease the energy barrier of the *CO2 hydrogenation step from 1.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Institute of Materials Science, Technische Universität Darmstadt, Peter-Grünberg-Str. 2, D-64287, Darmstadt, Germany.
The design of cathode/electrolyte interfaces in high-energy density Li-ion batteries is critical to protect the surface against undesirable oxygen release from the cathodes when batteries are charged to high voltage. However, the involvement of the engineered interface in the cationic and anionic redox reactions associated with (de-)lithiation is often ignored, mostly due to the difficulty to separate these processes from chemical/catalytic reactions at the cathode/electrolyte interface. Here, a new electron energy band diagrams concept is developed that includes the examination of the electrochemical- and ionization- potentials evolution upon batteries cycling.
View Article and Find Full Text PDFSci Rep
December 2024
Key Laboratory of Coalbed Methane Resource and Reservoir Formation Process, Ministry of Education, China University of Mining and Technology, Xuzhou, China.
This analysis revealed the alterations in the pore structure of large organic molecules in coal during the process of coal pyrolysis. Nine models of macromolecular structures in coals, representing distinct coal ranks, have been built. The research results show that along with the increasing coal rank, the average microporous volume of medium rank coal is 0.
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