Operando-informed precatalyst programming towards reliable high-current-density electrolysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrocatalysts are vital for industrial processes and decarbonization but suffer degradation due to operational changes.
• Designing stable and reliable electrocatalysts is challenging due to unpredictable structural and compositional evolution.

Purpose of the Study:

• To track and control the surface reconstruction of iron sulfides and oxides during the oxygen evolution reaction.
• To develop predictive design strategies for electrocatalysts by understanding and programming their activation.

Main Methods:

• Operando X-ray spectroscopy and computational modeling were employed to monitor catalyst behavior.
• Activation programming strategies were developed based on thermodynamics and kinetics of surface reconstruction.

Main Results:

• Inappropriate activation leads to uncontrolled iron oxidation and irreversible catalyst degradation.
• Programmed activation significantly improved durability in a NiₓFe₁₋ₓS₂ model system by threefold.
• Achieved a low cell degradation rate of 0.12 mV h⁻¹ over 550 h at high current densities (1 A cm⁻²).

Conclusions:

• Activation programming offers control over precatalyst oxidation, enabling reliable electrocatalyst design.
• This approach bridges predictive modeling and experimental design for enhanced electrocatalyst reliability.
• The findings are crucial for advancing industrial water electrolysis and other high-current-density applications.