A Bidirectional Nanomodification Approach for Synthesizing Hierarchically Architected Mixed Oxide Electrodes for...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Transition-metal oxides (Fe, Ni, Co) are promising, low-cost oxygen evolution reaction (OER) catalysts.
• Challenges include complex structuring, high Tafel slopes, and low stability, hindering practical use over Ir/Ru catalysts.

Purpose of the Study:

• To develop a novel strategy for constructing hierarchical mixed oxide electrocatalysts.
• To improve OER activity, stability, and reduce Tafel slopes for practical water splitting.

Main Methods:

• Hierarchical architecting of mixed oxides on conductive substrates (ITO, Ni foam) via nanosheet deposition and bidirectional nanomodification.
• Utilizing metal salts in aprotic polar solvents (acetone) for surface modification.
• Preparation of NiO-based nanosheets with nanopores/nanobranches containing up to four transition metals.

Main Results:

• Achieved a record-low Tafel slope of 22.3 mV·dec⁻¹ with FeMnNi-O nanosheets on Ni foam.
• Demonstrated week-long continuous operation durability.
• Successfully prepared NiO-based nanosheets with tunable hierarchical nanostructures.

Conclusions:

• Hierarchically designed mixed oxide electrodes offer a cost-effective route to high, stable OER catalytic activity.
• This approach facilitates new electrocatalyst design and advances practical water-splitting devices.