Pseudo-Ir Os_xPt_1-x Solid Solutions for Ir-Free H₂ Generation from N₂H₄ Decomposition

Area of Science:

• Materials Science
• Catalysis
• Energy Storage

Background:

• Iridium (Ir) is the most active catalyst for hydrogen (H₂) generation via hydrazine (N₂H₄) decomposition at room temperature.
• High cost and rarity of Ir necessitate the development of alternative catalysts for improved N₂H₄-based H₂ storage.

Purpose of the Study:

• To explore immiscible Os_xPt_1-x solid solutions as potential replacements for Ir catalysts.
• To investigate the catalytic activity of Os-Pt alloys for N₂H₄ decomposition and H₂ generation.

Main Methods:

• Synthesis of immiscible Os_xPt_1-x solid solutions.
• Evaluation of catalytic activity for N₂H₄ decomposition.
• Utilized *in situ* Fourier transform infrared spectroscopy (FTIR).
• Employed density-functional theory (DFT) calculations.

Main Results:

• Os_0.5Pt_0.5 exhibited significantly higher N₂H₄ decomposition activity than pure Ir.
• Os-Pt alloys, despite using less active elements, outperformed Ir.
• DFT and FTIR data suggest rapid N-N and N-H bond dissociation and H₂ formation on Os-Os, Os-Pt, and Pt-Pt sites.

Conclusions:

• Os_0.5Pt_0.5 acts as a highly effective pseudo-Ir catalyst for ultrafast H₂ generation.
• Os-Pt alloys present a viable, cost-effective strategy for advancing hydrogen storage technologies.