Reconstruction Induced Dynamic Incorporation of Zn Into Cobalt Hydroxide via Synergistic Structural Evolution for...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Surface reconstruction of electrocatalysts is crucial for enhancing catalytic activity.
• Cobalt molybdate (CoMoO4)-based electrocatalysts face challenges in hydrogen evolution reaction (HER) due to limited active sites and slow kinetics.

Purpose of the Study:

• To design a novel CoMoO4-based electrocatalyst with enhanced HER activity and durability.
• To investigate the synergistic structural evolution between CoMoO4 and ZnO for improved electrocatalysis.
• To understand the role of Zn doping in the reconstructed cobalt species for HER and seawater electrolysis.

Main Methods:

• Rational design of a CoMoO4 pre-catalyst loaded on ZnO nanorods.
• Inducing synergistic structural evolution via ZnO dissolution and CoMoO4 transformation.
• Characterization of the reconstructed electrocatalyst and evaluation of its HER performance.
• Density Functional Theoretical (DFT) calculations to elucidate the mechanism of enhancement and corrosion mitigation.

Main Results:

• The reconstructed electrocatalyst, featuring Zn-doped Co(OH)2, achieved a low HER overpotential of 40 mV at 10 mA cm⁻².
• Excellent HER performance was maintained in a simulated seawater electrolyte with an overpotential of 65 mV at 10 mA cm⁻².
• The anion exchange membrane (AEM) electrolyzer demonstrated remarkable durability, operating for 650 hours in water electrolysis and 1000 hours in seawater electrolysis.
• DFT calculations confirmed that Zn dopants enhance HER energetics and reduce Cl⁻-induced corrosion.

Conclusions:

• Synergistic structural co-evolution between ZnO and CoMoO4 leads to the formation of highly active and durable Zn-doped Co(OH)2 electrocatalysts.
• The developed electrocatalyst shows significant potential for efficient hydrogen production, particularly in challenging environments like seawater.
• This study offers valuable insights into designing advanced electrocatalysts through controlled structural evolution and doping strategies.