An Unconventional Phosphotungstate Constructed from Pentavacant [PW7O29]11- Building Blocks With Peroxidase-Like...

Area of Science:

• Inorganic Chemistry
• Materials Science
• Nanotechnology

Background:

• Polyoxometalates (POMs) are versatile inorganic clusters with diverse structures and applications.
• Highly lacunary POMs offer unique frameworks for incorporating functional elements.
• Nanozymes, mimicking natural enzymes, are increasingly explored for catalytic applications.

Purpose of the Study:

• To synthesize and characterize a novel phosphotungstate compound.
• To investigate the peroxidase-like catalytic activity of the synthesized compound.
• To develop a sensitive colorimetric method for hydrogen peroxide (H2O2) detection.

Main Methods:

• Single-crystal X-ray diffraction for structural characterization.
• Peroxidase-like activity assays using 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2.
• Steady-state kinetic studies to determine Michaelis constants (Km).
• Development and validation of a colorimetric detection method for H2O2.

Main Results:

• A new phosphotungstate, (CH6N3)10[Na2(H2O)4(P4W14O58)]·8H2O (1), was synthesized and structurally elucidated.
• Compound 1 exhibited high peroxidase-like activity, efficiently catalyzing TMB oxidation by H2O2 under acidic conditions.
• Kinetic analysis revealed strong substrate affinity (Km for TMB = 0.25 mM, Km for H2O2 = 3.73 mM).
• A colorimetric method for H2O2 detection was established with a linear range of 5-700 μM and a detection limit of 2.19 μM.

Conclusions:

• The synthesized phosphotungstate expands the structural diversity of highly lacunary POMs.
• Compound 1 shows promising potential as a POM-based nanozyme for catalytic applications.
• The developed colorimetric method offers a facile and sensitive approach for H2O2 detection.