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Single-Atom to Ultrasmall Au Nanoparticles Anchored on NiFe Layered Double Hydroxide as Catalyst for Oxygen and Hydrogen Evolution Reactions

Year: 2024

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Owing to the limited supply and high cost, the rational design of precious metal-based catalysts is of essential importance for boosting the electrocatalytic activity. Herein, the variation of Au species from single-atoms to ultrasmall nanoparticles (3–6 nm) deposited on NiFe-layered double hydroxide (NiFe-LDH) was investigated as a bifunctional electrocatalyst for oxygen and hydrogen evolution reactions. The brucite-like layered structure of NiFe-LDH was verified by X-ray diffraction. The existence of Au single-atom and ultrasmall nanoparticles as well as the local bonding environment of Au species were evaluated by high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The integration of Au into NiFe-LDH as single atoms and metallic nanoparticles shows significant improvement in the electrocatalytic activity in 1 M KOH. Single-atom Au/NiFe-LDH (2Au/NiFe-LDH, 0.21 wt % Au) delivers the lowest overpotential of 209 mV to catalyze 10 mA cm –2 OER current density with the Tafel slope of 46.5 mV dec –1 . On the other hand, Au nanoparticles/NiFe-LDH (50Au/NiFe-LDH, 3.22 wt % Au) possesses an overpotential of 150 mV at 10 mA cm –2 HER current density with the Tafel slope of 134.5 mV dec –1 . For overall water splitting, under the optimum conditions, the 2Au/NiFe-LDH//50Au/NiFe-LDH couple requires the cell potentials of 1.62 and 1.78 V to deliver the current density of 10 and 100 mA cm –2 in 1 M KOH. These findings provide insights into the effect of decoration of Au species on the NiFe-LDH catalyst surface for the efficient performance in the production of O 2 and H 2 in the alkaline electrolyte.

Source: ACS Applied Nano Materials

DOI: 10.1021/acsanm.4c05830