Capture and Photocatalytic Conversion of Low-Concentration CO₂ Using a Self-Assembled CdSe @Carbonic Anhydrase...

Area of Science:

• Materials Science
• Biotechnology
• Environmental Science

Background:

• Growing demand for efficient carbon capture and utilization (CCU) technologies, especially for low-concentration CO2.
• Photocatalytic CO2 conversion is promising but limited by low CO2 solubility and side reactions under dilute conditions.
• Need for improved catalysts that can effectively handle low CO2 concentrations.

Purpose of the Study:

• To design and synthesize a biohybrid system for enhanced CO2 capture and conversion.
• To improve the efficiency and selectivity of CO2 conversion, particularly at low concentrations.
• To investigate the synergistic effects within the biohybrid system for low-concentration CO2 utilization.

Main Methods:

• Self-assembly of a biohybrid system combining cadmium selenide quantum dots (CdSe QDs) with carbonic anhydrase (CA), denoted as CdSe@CA.
• Testing the CO2 conversion rate and selectivity of the CdSe@CA biohybrid under various CO2 concentrations (100%, 50%, 15%).
• Comparative analysis of the biohybrid's performance against CdSe QDs alone.
• Mechanistic studies to elucidate the synergistic effects between CA and CdSe QDs.

Main Results:

• The CdSe@CA biohybrid achieved a CO2 conversion rate of 47.3 μmol g⁻¹ h⁻¹ with 100% selectivity for CO production in a 100% CO2 atmosphere.
• Under 50% CO2 conditions, CdSe@CA maintained a high reduction rate, while CdSe QDs alone showed a significant drop to 7.6 μmol g⁻¹ h⁻¹.
• Even at 15% CO2 (simulated flue gas), the biohybrid demonstrated a CO2 capture and conversion rate of 8.2 μmol g⁻¹ h⁻¹.
• Mechanistic analysis indicated synergistic effects: CA enhanced CO2 accumulation and stabilized intermediates, boosting efficiency.

Conclusions:

• The developed CdSe@CA biohybrid system exhibits excellent efficiency and selectivity for capturing and converting low-concentration CO2.
• The synergistic interaction between carbonic anhydrase and CdSe quantum dots is key to overcoming limitations of dilute CO2 conditions.
• This study presents a viable and promising strategy for practical low-concentration CO2 capture and utilization applications.