The design of a low-iridium-loading anode catalyst layer with high activity and durability is a key challenge for a proton exchange membrane water electrolyzer (PEMWE). Here, the synthesis of a novel supported IrO nanocatalyst with a tri-layered structure, dubbed IrO@TaO@TaB that is composed of ultrasmall IrO nanoparticles anchored on amorphous TaO overlayer of TaB nanorods is reported. The composite electrocatalyst shows great activity and stability toward the oxygen evolution reaction (OER) in acid, thanks to its dual-interface structural feature. The electronic interaction in IrO/TaO interface can regulate the coverage of surface hydroxyl groups, the Ir/ Ir ratio, and the redox peak potential of IrO for enhancing OER activity, while the dense TaO overlayer can prevent further oxidation of TaB substrate and stabilize the IrO catalytic layers for improving structural stability during OER. The IrO@TaO@TaB can be used to fabricate an anode catalyst layer of PEMWE with an iridium-loading as low as 0.26 mg cm. The low-iridium-loading PEMWE delivers high current densities at low cell voltages (e.g., 3.9 A cm@2.0 V), and gives excellent activity retention for more than 1500 h at 2.0 A cm current density.
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http://dx.doi.org/10.1002/adma.202407717 | DOI Listing |
ACS Appl Mater Interfaces
December 2024
Department of Chemistry, Material Science Lab, Annamalai University, Annamalai Nagar, Tamilnadu 608 002, India.
Herein, we demonstrated that a polycrystalline cobalt oxide/borate (CoO-Bo) hybrid catalyst prepared by coprecipitation followed a simple annealing process with a viable boron source of less hazardous ammonium borate, an efficient electrocatalyst for the oxygen evolution reaction (OER). The borate species in the crystalline cobalt oxide lattice provides a tunable polycrystalline morphology with a defect-rich lattice and numerous grain boundaries in the CoO-Bo hybrid electrocatalyst, which significantly boosts the OER activity compared to the crystalline counterparts of CoO and precious IrO in a harsh alkaline electrolyte (1 M KOH). The borate modulated CoO-Bo achieves a 10 mA/cm geometrical current density for the OER with a very low overpotential (η) of 271 mV and small Tafel slope of 34 mV dec, in an inert glassy carbon (GC) support, while only requiring η of 267 and 32 mV dec in a 3D nickel foam (NF) support at the same current density.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
Department of Energy and Environmental Materials, Suzhou Laboratory, 388 Ruoshui Road, Suzhou, China. Electronic address:
The sluggish kinetics, poor stability, and high iridium loading in acidic oxygen evolution reaction (OER) present significant challenges for proton exchange membrane water electrolyzers (PEMWE). While supported catalysts can enhance the utilization and activity of Ir atoms, they often fail to mitigate the detrimental effects of over-oxidation and dissolution of Ir. Here, we leverage the redox properties of the Mn/Mn couple as electronic modulators to develop a low-iridium, durable electrocatalyst for acidic OER.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Institut National de la Recherche Scientifique (INRS), Centre Énergie Matériaux Télécommunications, Varennes, Québec, J3X 1P7, Canada.
The production of storable hydrogen fuel through water electrolysis powered by renewable energy sources such as solar, marine, geothermal, and wind energy presents a promising pathway toward achieving energy sustainability. Nevertheless, state-of-the-art electrolysis requires support from ancillary processes which often incur financial and energy costs. Developing electrolysers capable of directly operating with water that contains impurities can circumvent these processes.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Department of Chemical Engineering, Hanyang University (Seoul Campus), 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
A promising approach to energy-efficient hydrogen production is coupling the hydrogen evolution reaction (HER) with the urea oxidation reaction (UOR), significantly reducing the energy requirements. However, achieving a low-cost yet high-performance electrocatalyst for both HER and UOR remains challenging. Here, we present a facile method for synthesizing nanoporous nickel sulfide (NiS) and nickel hexacyanoferrate (NiHCF) nanocubes directly on nickel foam (NF) without any added nickel source using a cyclic voltammetry technique.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
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