Water oxidation is a crucial reaction for renewable energy conversion and storage. Among the alkaline oxygen evolution reaction (OER) catalysts, NiFe based oxyhydroxides show the highest catalytic activity. However, the details of their OER mechanism are still unclear, due to the elusive nature of the OER intermediates. Here, using a novel differential electrochemical mass spectrometry (DEMS) cell interface, we performed isotope-labelling experiments in O-labelled aqueous alkaline electrolyte on Ni(OH) and NiFe layered double hydroxide nanocatalysts. Our experiments confirm the occurrence of Mars-van-Krevelen lattice oxygen evolution reaction mechanism in both catalysts to various degrees, which involves the coupling of oxygen atoms from the catalyst and the electrolyte. The quantitative charge analysis suggests that the participating lattice oxygen atoms belong exclusively to the catalyst surface, confirming DFT computational hypotheses. Also, DEMS data suggest a fundamental correlation between the magnitude of the lattice oxygen mechanism and the faradaic efficiency of oxygen controlled by pseudocapacitive oxidative metal redox charges.
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http://dx.doi.org/10.1002/anie.202101698 | DOI Listing |
J Phys Chem Lett
January 2025
Graphene Composite Research Center, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, P. R. China.
The oxygen evolution reaction (OER) is a critical half-reaction in water splitting and metal-air cells. The sensitivity of the OER to the composition and structure of the electrocatalyst presents a significant challenge in elucidating the structure-property relationship. In this study, highly stable single-crystal cobalt carbonate hydroxide [Co(OH)CO, CoCH] was used as a model to investigate the correlations among structure, composition, and reactivity.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Department of Physics, Indian Institute of Technology Delhi (IITD), Delhi 110016, India.
The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are considered to be the most important processes in metal-air batteries and regenerative fuel cell devices. Metal-organic polymers are attracting interest as promising precursors of advanced metal/carbon electrocatalysts because of their hierarchical porous structure along with the integrated metal-carbon framework. We developed carbon-coated CNTs with Ni/Fe and Cu/Fe as active sites.
View Article and Find Full Text PDFNanomicro Lett
January 2025
State Key Laboratory of Heavy Oil Processing, College of New Energy, China University of Petroleum (East China), Qingdao, 266580, People's Republic of China.
Seawater electrolysis offers a promising pathway to generate green hydrogen, which is crucial for the net-zero emission targets. Indirect seawater electrolysis is severely limited by high energy demands and system complexity, while the direct seawater electrolysis bypasses pre-treatment, offering a simpler and more cost-effective solution. However, the chlorine evolution reaction and impurities in the seawater lead to severe corrosion and hinder electrolysis's efficiency.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
School of Physics, Beihang University, Beijing 100191, China.
Exploiting biomimetic perception of invisible spectra in flexible artificial human vision systems (HVSs) is crucial for real-time dynamic information processing. Nevertheless, the fast processing of motion objects in natural environments poses a challenge, necessitating that these artificial HVSs simultaneously have swift photoresponse and nonvolatile memory. Here, inspired by the human retina, we propose a flexible UV neuromorphic visual synaptic device (NeuVSD) based on GaO@GaN-composited nanowires for dynamic visual perception.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
Electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is a promising alternative for oxygen evolution reactions. The search for efficient catalysts has been attracting increasing scientific attention. This work explores the performance of nitrogen-doped graphene-supported single-atom catalysts (M-NC SACs) for the reaction.
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