NiFe-based (oxy)hydroxides are the benchmark catalysts for the oxygen evolution reaction (OER) in alkaline medium, however, it is still challenging to control their structures and compositions. Herein, molybdates (NiFe(MoO ) ) are applied as unique precursors to synthesize ultrafine Mo modified NiFeO H (oxy)hydroxide nanosheet arrays. The electrochemical activation process enables the molybdate ions (MoO ) in the precursors gradually dissolve, and at the same time, hydroxide ions (OH ) in the electrolyte diffuse into the precursor and react with Ni and Fe ions in confined space to produce ultrafine NiFeO H (oxy)hydroxides nanosheets (<10 nm), which are densely arranged into microporous arrays and maintain the rod-like morphology of the precursor. Such dense ultrafine nanosheet arrays produce rich edge planes on the surface of NiFeO H (oxy)hydroxides to expose more active sites. More importantly, the capillary phenomenon of microporous structures and hydrophilic hydroxyl groups induce the superhydrophilicity and the rough surface produces the superaerophobic characteristic for bubbles. With these advantages, the optimized catalyst exhibits excellent performance for OER, with a small overpotential of 182 mV at 10 mA cm and long-term stability (200 h) at 200 mA cm . Theoretical calculations show that the modification of Mo enhances the electron delocalization and optimizes the adsorption of intermediates.
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http://dx.doi.org/10.1002/smll.202301609 | DOI Listing |
Chemistry
December 2024
Technische Universitat Berlin, Chemistry, Strasse des 17. Juni 135, Sekr. C2, 10623, Berlin, GERMANY.
Water-assisted electrocatalytic oxidation of alcohols into valuable chemicals is a promising strategy to circumvent the sluggish kinetics of water oxidation, while also reducing cell voltage and improving energy efficiency. Recently, transition metal (TM)-based catalysts have been investigated for anodic alcohol oxidation, but success has been limited due to competition from the oxygen evolution reaction (OER) within the working regime. In this study, NiCo-based Prussian blue analog (PBA) was electrochemically activated at the anodic potential to produce a Co-Ni(O)OH active catalyst with a nanosheet-like architecture.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
School of Materials Science & Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
Small
November 2024
Chemistry and Chemical Engineering Guangdong Laboratory, Shantou, 515063, P. R. China.
Small
December 2024
Department of Organic Materials and Textile Engineering, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do, 54896, Republic of Korea.
Investigating advanced electrocatalysts is crucial for improving the efficacy of water splitting to generate environmentally friendly fuel. The discovery of highly effective electrocatalysts, capable of driving oxygen evolution reaction (OER) and urea oxidation reaction (UOR) in urea-alkaline environments, is pivotal for advancing large-scale hydrogen production. This study aims to introduce a new method that involves creating nanosheets of high-loading iridium single atoms embedded in a manganese-containing nickel oxyhydroxide matrix (Ir@Mn─NiOOH).
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2024
Chemical Engineering Group Engineering and Technology Institute Groningen (ENTEG), University of Groningen, 9747 AGGroningen The Netherlands.
A novel oxygen evolution reaction (OER) electrocatalyst was prepared by a synthesis strategy consisting of the solvothermal growth of NiS nanostructures on Ni foam, followed by hydrothermal incorporation of Fe species (Fe-NiS/Ni foam). This electrocatalyst displayed a low OER overpotential of 230 mV at 100 mA·cm, a low Tafel slope of 43 mV·dec, and constant performance at an industrially relevant current density (500 mA·cm) over 100 h in a 1.0 M KOH electrolyte, despite a minor loss of Fe in the process.
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