Amorphous Intermediate Derivative from ZIF-67 and Its Outstanding Electrocatalytic Activity

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Increasing active sites is crucial for enhancing catalyst activity.
• Amorphous materials are recognized for their abundant catalytic sites.
• ZIF-67 is a precursor for cobalt-based catalysts.

Purpose of the Study:

• To synthesize amorphous cobalt oxide derivatives from ZIF-67.
• To evaluate the catalytic performance of amorphous derivatives for oxygen evolution reaction (OER) and nonenzymatic glucose sensing.
• To compare the activity of amorphous catalysts with crystalline cobalt oxide.

Main Methods:

• Low-temperature heat treatment of ZIF-67 hollow spheres at varying temperatures.
• Characterization of the intermediate amorphous product.
• Electrochemical evaluation for OER and glucose sensing.

Main Results:

• An amorphous intermediate product was formed at 260 °C.
• The amorphous derivative showed significantly higher catalytic activity than crystalline Co3O4.
• For OER, the amorphous catalyst had a low overpotential of 352 mV at 10 mA cm⁻².
• For glucose sensing, it offered a low detection limit (3.9 × 10⁻⁶ M) and high sensitivity (1074.22 µA mM⁻¹ cm⁻²).

Conclusions:

• Low-temperature heat treatment of ZIF-67 yields amorphous cobalt oxide with superior catalytic properties.
• The amorphous structure provides abundant active sites, enhancing performance in OER and glucose sensing.
• Amorphous cobalt oxide is a promising electrocatalyst for energy and sensing applications.