Zinc Single-Atom Nanozyme As Carbonic Anhydrase Mimic for CO₂ Capture and Conversion

Area of Science:

• Materials Science
• Nanotechnology
• Biochemistry

Background:

• Single-atom nanozymes (SANs) are engineered nanomaterials that replicate the function of metalloenzymes.
• Carbonic anhydrase is a crucial enzyme involved in CO2 hydration.
• Developing efficient artificial mimics for enzymatic activity is a key research area.

Purpose of the Study:

• To synthesize and characterize a zinc-nitrogen-carbon single-atom nanozyme (Zn-SAN) that mimics carbonic anhydrase activity.
• To evaluate the CO2 capture and conversion capabilities of the synthesized Zn-SAN.
• To explore the potential of Zn-SAN for amino acid detection and quantification.

Main Methods:

• A two-step annealing technique was employed for the synthesis of Zn-SAN, achieving high metal loading (>18 wt%).
• CO2 capture and conversion were assessed by reacting Zn-SAN with CO2 and buffer solutions, followed by precipitation of CaCO3.
• Amino acid detection involved utilizing the inhibitory effect of specific amino acids on Zn-SAN's enzymatic activity.

Main Results:

• The synthesized Zn-SAN exhibited superior catalytic activity due to high zinc loading.
• Zn-SAN demonstrated a CO2 uptake of 2.3 mmol/g and over 91% conversion to bicarbonate.
• The CO2 sequestration capacity was determined to be 42 mg CaCO3/mg Zn-SAN.
• Zn-SAN enabled sensitive detection of histidine, cysteine, glutamic acid, and aspartic acid with low micromolar detection limits.

Conclusions:

• The developed Zn-SAN effectively mimics carbonic anhydrase, offering a promising material for CO2 capture and conversion.
• The high catalytic efficiency and CO2 sequestration capacity highlight the potential of SANs in environmental applications.
• The use of Zn-SAN for amino acid detection demonstrates its versatility and applicability in biochemical analysis and quality control.