Water oxidation using a cobalt monolayer prepared by underpotential deposition

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalysts are crucial for water-to-dioxygen conversion in chemical applications.
• Challenges include uncertainties in catalyst loading and determining wetted surface area.

Purpose of the Study:

• To develop a method for precisely determining electrocatalyst surface area and activity.
• To investigate cobalt monolayers on gold electrodes for water oxidation.

Main Methods:

• Underpotential deposition of cobalt on a gold electrode.
• Characterization using atomic force microscopy, grazing-incidence X-ray diffraction, and X-ray photoelectron spectroscopy.
• Electrochemical evaluation of water oxidation efficiency.

Main Results:

• A cobalt monolayer electrocatalyst was successfully prepared and characterized.
• An enhancement in current density was observed with the addition of phosphate ions.
• Current densities at 500 mV overpotential: 0.20 mA/cm² (gold), 0.74 mA/cm² (cobalt), and 2.4 mA/cm² (cobalt in PO4³⁻).

Conclusions:

• The developed approach allows for accurate determination of electrocatalyst surface area and activity.
• Surface-bound ligands, like phosphate, can enhance water oxidation efficiency.