Cu/Ag Complex Modified Keggin-Type Coordination Polymers for Improved Electrochemical Capacitance, Dual-Function...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Polyoxometalates (POMs) are versatile inorganic clusters with tunable properties.
• Enhancing the electrochemical performance of POMs is crucial for energy storage and catalysis.
• Porous coordination polymers offer unique structural and functional advantages.

Purpose of the Study:

• To synthesize novel porous coordination polymers by incorporating metal-organic units into POM systems.
• To evaluate the electrochemical properties, including specific capacitance and cyclic stability, of the synthesized materials.
• To investigate the electrocatalytic activity and sensing performance of the new POM-based compounds.

Main Methods:

• Hydrothermal synthesis of three distinct porous coordination polymers: {Cu(pra)2}[{Cu(pra)2}3{PMo11VIMoVO40}] (1), [{Ag5(pz)6(H2O)0.5Cl}{PMo11VIMoVO40}] (2), and [{Cu3(bpz)5(H2O)}{PMo12O40}] (3).
• Electrochemical characterization using cyclic voltammetry and galvanostatic charge-discharge.
• Electrocatalytic activity assessment for peroxide reduction and ascorbic acid oxidation.
• Sensing performance evaluation for ascorbic acid and hydrogen peroxide detection.

Main Results:

• Compounds 1-3 exhibited significantly enhanced specific capacitances (672.2–782.1 F g−1 at 2.4 A g−1) compared to the parent Keggin cluster.
• Superior cyclic stability was observed, with compounds 1-3 retaining 91.5%, 89.3%, and 87.8% efficiency after 5000 cycles, respectively.
• Excellent electrocatalytic activity for H2O2 reduction and AA oxidation was demonstrated, with compound 2 showing outstanding sensing capabilities.

Conclusions:

• The introduction of metal-organic units effectively boosts the capacitance performance of POMs.
• Enhanced redox centers, stable porous structures, and improved ion/electron transfer contribute to superior electrochemical properties.
• The synthesized POM-based coordination polymers show great potential for applications in supercapacitors, electrocatalysis, and chemical sensing.