Phase control of solid-solution RuIn nanoparticles and their catalytic properties.

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Solid properties are significantly influenced by their crystal structures.
• Controlling crystal phases in bimetallic nanoparticles is crucial for tuning their properties.
• The hydrogen evolution reaction (HER) is a key process for sustainable energy production.

Purpose of the Study:

• To achieve phase control of solid-solution Ruthenium-Iridium (RuIn) nanoparticles (NPs) from face-centred cubic (fcc) to hexagonal close-packed (hcp) structures.
• To investigate the effect of these crystal structures on the catalytic performance in the hydrogen evolution reaction (HER).
• To correlate the observed catalytic activity with the intrinsic electronic structures of the NPs.

Main Methods:

• Hydrogen heat treatment was employed for phase control of RuIn NPs.
• Catalytic performance was evaluated using the hydrogen evolution reaction (HER).
• Valence-band X-ray photoelectron spectroscopy (VB-XPS) was used to analyze the electronic structures.

Main Results:

• Phase control of RuIn NPs from fcc to hcp was successfully achieved for the first time.
• Hexagonal close-packed (hcp) RuIn NPs exhibited enhanced HER catalytic performance compared to fcc RuIn NPs and monometallic Ru NPs.
• VB-XPS revealed a deeper d-band center in hcp RuIn NPs, correlating with improved HER activity.

Conclusions:

• Hydrogen heat treatment enables tunable phase control of RuIn NPs.
• The hcp crystal structure of RuIn NPs is beneficial for enhanced HER catalytic activity.
• The electronic structure, specifically the d-band center, plays a critical role in the catalytic performance of RuIn NPs for HER.