High-entropy alloys in a radial mesostructured TiO₂ support for efficient hydrogen evolution

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• High-entropy alloys (HEAs) are promising electrocatalysts due to synergistic effects and tunable structures.
• However, HEA nanoparticles face aggregation and degradation issues, limiting their practical application.
• Noble-metal reduction is a key goal in catalyst development.

Purpose of the Study:

• To develop a stable and highly active electrocatalyst by overcoming HEA nanoparticle limitations.
• To integrate HEA nanoparticles within a structured support for enhanced performance.
• To explore the potential of HEA-mesoporous TiO2 for hydrogen evolution and hydrazine splitting.

Main Methods:

• A spatial confinement strategy combining cooperative self-assembly and solvothermal processing.
• Uniform encapsulation of PtCuFeCoNi HEA nanoparticles within radially ordered mesoporous TiO2 channels.
• Electrochemical characterization including hydrogen evolution reaction (HER) and hydrazine oxidation kinetics.

Main Results:

• The synthesized HEA-mesoporous TiO2 composite catalyst demonstrated outstanding HER activity (31 mV overpotential at 10 mA cm-2) and low Tafel slope (24 mV dec-1).
• The catalyst exhibited excellent durability over 200 hours for HER and favorable kinetics for hydrazine oxidation.
• The composite enabled energy-efficient overall hydrazine splitting with a 1.25 V cell voltage reduction compared to water splitting.

Conclusions:

• The developed HEA-mesoporous TiO2 catalyst offers a viable strategy for integrating HEAs with ordered mesoporous oxide supports.
• This approach leads to highly active and durable electrocatalysts for energy-saving hydrogen production.
• The study highlights the potential of synergistic effects between HEAs and mesoporous structures for advanced energy applications.