Single-Step Direct Laser Writing of Multimetal Oxygen Evolution Catalysts from Liquid Precursors

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Developing efficient and cost-effective catalysts for the oxygen evolution reaction (OER) is crucial for energy technologies.
• Traditional synthesis methods can be time-consuming and expensive, limiting catalyst exploration.

Purpose of the Study:

• To investigate a laser direct-write method for synthesizing metastable mixed transition metal oxides.
• To evaluate the OER performance of these novel catalysts.
• To understand the structure-activity relationships governing their catalytic behavior.

Main Methods:

• Laser direct-write synthesis from solution precursors.
• Reactive force-field Monte Carlo simulations for structural analysis.
• Electrochemical testing to evaluate OER performance (Tafel slope, overpotential).
• Density-functional theory (DFT) calculations to elucidate active site mechanisms.

Main Results:

• Rapid synthesis of diverse heterogeneous alloy/oxide catalysts with nanocrystalline inclusions in an amorphous matrix.
• A stable Fe$_{0.63}$Co$_{0.19}$Ni$_{0.18}$O$_{x}$/C catalyst achieved a Tafel slope of 38.23 mV dec$^{-1}$ and overpotential of 247 mV.
• Higher iron content and less crystalline structures were found to decrease charge transfer resistance, enhancing electrocatalytic activity.
• DFT calculations confirmed that distorted active sites in ternary metal catalysts lower OER overpotentials.

Conclusions:

• Laser direct-write is an effective method for rapid catalyst synthesis.
• Ternary iron-cobalt-nickel oxides show promising OER performance, competitive with iridium oxide.
• Catalyst structure, particularly iron content and amorphousness, significantly impacts OER activity.