Electronic-Structure Modulation in NiRu Alloys To Alleviate Hydrogen Poisoning for Robust Photothermal Ammonia...

Area of Science:

• Materials Science
• Catalysis
• Renewable Energy

Background:

• Ammonia (NH3) is a key hydrogen carrier, but its decomposition is hindered by catalyst poisoning from intermediates like hydrogen.
• Developing cost-effective, active, and durable catalysts resistant to poisoning is crucial for efficient hydrogen production.

Purpose of the Study:

• To develop a Ni-Ru alloy catalyst for efficient photothermal ammonia decomposition.
• To investigate the catalyst's activity, stability, and resistance to hydrogen poisoning.

Main Methods:

• Synthesis and characterization of Ni-Ru alloy catalysts.
• Photothermal ammonia decomposition experiments under irradiation.
• Density Functional Theory (DFT) calculations to understand catalytic mechanisms.

Main Results:

• The Ni40Ru60 catalyst demonstrated lower apparent activation energy (71.36 kJ·mol-1) compared to Ru (78.68 kJ·mol-1).
• Achieved a hydrogen production rate of 3.1 mol·gcat-1·h-1 over Ni40Ru60, significantly higher than Ru (1.7 mol·gcat-1·h-1).
• Exhibited near-zero reaction order (0.13) in H2/NH3 atmosphere, indicating suppressed hydrogen poisoning and stable operation beyond 2500 hours.

Conclusions:

• Ni-Ru alloying effectively weakens intermediate adsorption and suppresses hydrogen poisoning by downshifting the Ru d-band center.
• The Ni40Ru60 catalyst offers a promising, stable, and practical pathway for hydrogen production via ammonia decomposition using photothermal energy.