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For NiFe-based precatalysts, there is a general consensus that they will undergo reconstruction to generate NiFe (oxy)hydroxides as real active sites during the electrochemical oxygen evolution reaction (OER), but the current understanding of the reconstruction process is still far from satisfactory. Herein, iron phosphates/molybdates on nickel foams (FPM/NF, = 5, 7, 10, 20) were prepared via a coprecipitation method, where although both MoO and PO undergo anion exchange during the activation process, i.e., dual reconstructions, to form NiFe (oxy)hydroxides, they show disparate reconstruction dynamics. By tuning the phosphates/molybdates ratio, the morphology, activity, and activation rate of the formed NiFe (oxy)hydroxides can be tuned. Consequently, the obtained optimal FP7M/NF-activated (FP7M/NF-a) possesses a fast and deep reconstruction with a morphology of nanoparticles with a disordered structure and rich oxygen vacancies, thus exhibiting exceptional OER activity (overpotentials of only 175 and 180 mV at 50 and 100 mA·cm) and excellent stability.
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http://dx.doi.org/10.1021/acs.jpclett.5c01711 | DOI Listing |
ACS Nano
September 2025
Eastern Institute for Advanced Study, Eastern Institute of Technology, Ningbo, Zhejiang 315200, P. R. China.
Ni-Fe (oxy)hydroxides are among the most active oxygen evolution reaction (OER) catalysts in alkaline media. However, achieving precise control over local asymmetric Fe-O-Ni active sites in Ni-Fe oxyhydroxides for key oxygenated intermediates' adsorption steric configuration regulation of the OER is still challenging. Herein, we report a two-step dealloying strategy to fabricate asymmetric Fe-O-Ni pair sites in the shell of NiOOH@FeOOH/NiOOH heterostructures from NiFe Prussian blue analogue (PBA) nanocubes, involving anion exchange and structure reconstruction.
View Article and Find Full Text PDFChemistry
September 2025
Department of Molecular Theory and Spectroscopy, Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der Ruhr, Germany.
In this study, we seek to deepen the understanding of the Fe effect in Ni-oxyhydroxide-mediated oxygen evolution reaction (OER) electrocatalysis in alkaline conditions, where extremely small amounts of Fe can have a dramatic impact on catalytic performance. For this purpose, Density Functional Theory (DFT) electronic structure calculations with implicit solvation description is employed in a constant pH/potential simulation framework. Nanoparticle models are considered for the nickel-based oxyhydroxide material with different degrees of Fe incorporation, and the pH/U-dependent interface structure is studied.
View Article and Find Full Text PDFNano Lett
September 2025
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
Constructing heterogeneous dual-site catalysts is anticipated for oxygen evolution reaction (OER). However, compared to the adsorbate evolution mechanism (AEM), the triggering oxide pathway mechanism (OPM) for catalysts poses challenges due to elusive structural evolution and low intrinsic activity. Herein, considering the distinct adsorption propensity of heterogeneous Ni-Fe sites toward differential intermediates (OH-O), the PO-induced deep reconstruction triggers a dual-site Ni-Fe discrepant oxide pathway mechanism (DOPM) for R-PO-NiCoFeOOH.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2025
School of Advanced Energy and IGCME, Sun Yat-Sen University (Shenzhen), Shenzhen, 518107, China.
The oxygen evolution reaction (OER), a bottleneck in electrochemical water splitting, is fundamentally limited by a scaling relationship between the binding energies of key intermediates (OH* and OOH*), imposing a minimum theoretical overpotential of 0.37 eV. Breaking this scaling relationship is crucial for enhancing OER activity, yet effective strategies remain scarce.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China.
The performance of oxygen evolution reaction (OER) catalysts heavily depends on intrinsically active and robust sites as well as high active site number, which poses challenges in catalyst design concerning composition and structure. This study presents a general oxygen-vacancy anchoring strategy for preparing oxide-based 4d/5d transition metal single-atom 2D materials as efficient and robust OER catalysts. In a typical synthesis, Keggin-structure polyoxometalate [PWO] clusters decompose into tetrahedral WO anions, which in situ adhere to the newly nucleated metal (Co, Fe, Ni) hydroxide (M(OH)) due to the latter's abundant oxygen vacancies, ensuring a uniform distribution of W single atoms.
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