Nickel catalysts are not as good as their noble metal counterparts for hydrogen oxidation in alkaline environments. They only have 1-2% of their activity. This is a problem because scientists don't fully understand why. But recent research sheds some light on this issue.

The study looked at how different anions, like OH

-

, Br

-

, Cl

-

, and SCN

-

, affect the hydrogen oxidation reaction (HOR) in nickel-based catalysts. The findings were interesting. Br

-

 and Cl

-

 ions stick to the catalyst's surface. This helps speed up hydrogen transfer, making the reaction more efficient. Plus, these ions also block OH

-

 from sticking, which prevents the nickel from oxidizing.

This anion adsorption trick improved the HOR activity of the NiMoO

x

 catalyst by 13%. It also delayed the start of nickel oxidation by 40 mV. However, not all anions are helpful. SCN

-

 ions, which are pseudohalogens, are a problem. They stick too tightly to the nickel, poisoning the catalyst and making it less effective.

The research showed that using Cl

-

-modified NiMoO

x

 catalysts in alkaline anion exchange membrane fuel cells can boost peak power density to 234. 3 mW cm

-2

. This is 24% higher than unmodified NiMoO

x

.

This study highlights the importance of anion adsorption in improving the performance of nickel-based catalysts. It's a step forward in making these catalysts more viable for practical applications.

ANION ADSORPTION

Nickel Catalysts Get a Boost from Halogen Friends

Continue reading...