Enriched Fe Doped on Amorphous Shell Enable Crystalline@Amorphous Core-Shell Nanorod Highly Efficient Electrochemical Water Oxidation

The rational design of efficient and cost-effective electrocatalysts for oxygen evolution reaction (OER) with sluggish kinetics, is imperative to diverse clean energy technologies. The performance of electrocatalyst is usually governed by the number of active sites on the surface. Crystalline/amorphous heterostructure has exhibited unique properties and opens new paradigms toward designing electrocatalysts with abundant active sites for improved performance. Hence, Fe doped Ni-Co phosphite (Fe-NiCoHPi) electrocatalyst with cauliflower-like structure, comprising crystalline@amorphous core-shell nanorod, is reported. The experiments uncover that Fe is enriched in the amorphous shell due to the flexibility of the amorphous component. Further density functional theory calculations indicate that the strong electronic interaction between the enriched Fe in the amorphous shell and crystalline core host at the core-shell interface, leads to balanced binding energies of OER intermediates, which is the origin of the catalyst-activity. Eventually, the Fe-NiCoHPi exhibits remarkable activity, with low overpotentials of only 206 and 257 mV at current density of 15 and 100 mA cm-2 . Unceasing durability over 90 h is achieved, which is superior to the effective phosphate electrocatalysts. Although the applications at high current remain challenges , this work provides an approach for designing advanced OER electrocatalysts for sustainable energy devices.

Fabrication of Trimetallic Fe-Co-Ni Electrocatalysts for Highly Efficient Oxygen Evolution Reaction

The development of inexpensive and well-activated water-splitting catalysts is required to reduce the use of conventional fossil fuels. In this study, a trimetallic Fe-Co-Ni catalyst was fabricated using a simple ion electrodeposition method. The metal deposition was performed using cyclic voltammetry, which was more efficient than constant-voltage deposition and significantly increased the stability of the catalyst. The synthesized material presented the morphology of a nanoflower in which the nanosheets were agglomerated. The Fe-Co-Ni catalyst exhibited excellent oxygen evolution reaction (OER) properties because the charge-transfer rate was improved owing to the synergistic effect of the metals. The OER was performed in a 1 M KOH solution using a three-electrode system, and the overpotential was 302 mV at 100 mA/cm². In addition, the Fe-Co-Ni catalyst exhibited excellent stability in alkaline solution for more than 48 h at 200 mA/cm². The results show that the method for preparing Fe-Co-Ni significantly improves its catalytic activity, and the resulting material could be used as an economical and efficient catalyst in future.