Magnetic Field Enhancing the Electrocatalytic Oxygen Evolution Reaction of FeMn-Based Spinel Oxides

For the widespread application of electrolytic water hydrogen production technology, it is crucial to prepare electrolytic water catalysts via inexpensive and abundant transition metals. Commercially, Mn3O4 can be utilized extensively since it is cheap, abundant, and stable, but its electrocatalytic performance still needs to be enhanced. In this paper, we adopted the conventional hydrothermal method to introduce Fe atoms into Mn3O4 to form spinel-structured FeMn oxides on Ni foam (marked as FexMn3–xO4); then, an external magnetic field was applied to further improve its oxygen evolution reaction (OER) performance. The overpotential of FeMn2O4 is 258 mV (current density at 20 mA·cm–2), and the Tafel slope is 28.7 mV·dec–1 when the magnetic field strength is 105 mT and the angle between the electric field and the magnetic field is 45°. The introduction of Fe and the synergistic effect of the mixed Mn and Fe promote the reaction kinetics and thus improve the OER performance of Mn3O4. The enhanced performance of FexMn3–xO4 under the magnetic field may mainly originate from the magnetohydrodynamic (MHD) effect, charge transfer effect, and energy effect

Probing the Crystal Plane Effect of Co₃O₄ for Enhanced Electrocatalytic Performance toward Efficient Overall Water Splitting

Identifying effective methods to enhance the properties of catalysts is urgent to broaden the scanty technologies, so far. Herein, we synthesized four Co₃O₄ crystals with different crystal planes and explored the crystal planes’ effects on electrochemical water splitting through theoretical and experimental studies for the first time. The results illustrate that the correlation of catalytic activity is established as {111} > {112} > {110} > {001}. Co₃O₄ crystals exposed with {111} facets show the highest OER (oxygen evolution reaction) and HER (hydrogen evolution reaction) activities. Upon fabrication in an alkaline electrolyzer, the bifunctional {111}∥{111} couple manifests the highest catalytic activity and satisfying durability for overall water splitting. Density functional theory (DFT) explains that the {111} facet possesses the biggest dangling bond density, highest surface energy, and smallest absolute value of Δ<i>G</i>_H*, leading to the enhanced electrocatalytic performance. This work will broaden our vision to improve the activity of various electrocatalysts by selectively exposing the specific crystal planes

New Efficient Electrocatalyst for the Hydrogen Evolution Reaction: Erecting a V₂Se₉@Poly(3,4-ethylenedioxythiophene) Nanosheet Array with a Specific Active Facet Exposed

To obtain catalysts with remarkable activity for the hydrogen evolution reaction (HER), rational design and synthesis of catalysts with rich active sites are very urgent. Herein, we reported, for the first time, V₂Se₉ nanosheet arrays exposed with the highly active (100) facet as a new efficient catalyst for HER. The highly active but thermodynamically instable (100) facet was converted from V₂O₅ based on a low crystal-mismatch strategy. Furthermore, conductive poly­(3,4-ethylenedioxythiophene) (PEDOT) acting as a co-catalyst further contributed to the redistribution of charge and reduction of hydrogen adsorption energy. Due to the strong synergistic effect between V₂Se₉ and PEDOT, the resulting material, noted as V₂Se₉@PEDOT NSs/NF, exhibited excellent electrocatalytic performance among selenide catalysts, for example, a small overpotential of 72 mV at 10 mA cm^–2, a low Tafel slope of 36.5 mV dec^–1, and remarkable durability. Simultaneously, density functional theory (DFT) computations proved that the adsorption free energy of H* (Δ<i>G</i>_H*) for V₂Se₉@PEDOT NSs/NF (0.09 eV) is comparable to that of Pt (around 0.09 eV)

Summary of SNP validation.

<p>Summary of SNP validation.</p

SNP distribution among scaffolds.

<p>The X-axis represents scaffold size (number of SNPs per scaffold)</p

Identification of expressed <i>Claudin</i> genes containing SNPs.

<p>Identification of expressed <i>Claudin</i> genes containing SNPs.</p

The genome distribution of the mapped reads.

<p>The genome distribution of the mapped reads.</p

Classification of putative SNPs.

<p>Inter-genic SNPs were identified from regions between genes, while Down_stream(+1 k) and Up_stream(−1 k) represents SNPs identified from regions of 1 kb downstream and upstream of the genes.</p

Distribution of minor allele frequencies (MAFs) of SNPs identified from the <i>T. rubirpes</i> swimbladder.

<p>The X-axis represents the SNP minor allele frequency in percentage, while the Y-axis represents the number of SNPs with given minor allele frequency</p

KEGG biochemical mappings for genes containing SNPs.

<p>KEGG biochemical mappings for genes containing SNPs.</p