Strontium-Induced Lattice Oxygen Activation in Pr-Based Perovskites for High-Efficiency Water Oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient, low-cost, noble-metal-free catalysts is crucial for alkaline water electrolysis and green hydrogen production.
• The oxygen evolution reaction (OER) is a key bottleneck in water splitting.

Purpose of the Study:

• To design a novel perovskite catalyst with enhanced OER performance using a "composition-thermal history" strategy.
• To investigate the synergistic effects of A-site doping and thermal treatment on catalyst nanostructure and OER activity.

Main Methods:

• Controlled A-site Sr²⁺ doping of Pr-based perovskite.
• High-temperature sintering at 950°C.
• Electrochemical characterization in 1 M KOH, including OER activity and durability tests.

Main Results:

• The synthesized Pr_0.75Sr_0.25Ni_0.7Co_0.3O₃ (PSNC-25) catalyst exhibited unique nanostructuring and maximized oxygen vacancies.
• Sr doping reduced oxygen vacancy formation energy, facilitating lattice oxygen-mediated OER.
• PSNC-25 achieved a low overpotential of 389 mV at 10 mA cm^-2 and a Tafel slope of 83 mV dec^-1, with robust durability over 120 hours.

Conclusions:

• The developed "composition-thermal history" approach effectively activates lattice oxygen-mediated mechanisms in cost-effective perovskites.
• This work provides a rational framework for designing advanced catalysts for scalable green hydrogen production.