Electrospun Zr-Doped CaO Sorbent for CO₂ Capture

A Zr-doped CaO sorbent for high-temperature CO₂ capture was fabricated using electrospinning. The nanofiber sorbent with an average filament diameter of about 160 nm is characterized by an initial CO₂ uptake capacity of 12.1 mmol/g, a specific surface area of 79 m²/g, an indentation Young's modulus of 520 MPa, and a hardness of 1.6 MPa. After 50 carbonation/decarbonation cycles, the sorbent has a decent CO₂ uptake capacity of 9.7 mmol/g due to the uniform distribution of CaZrO₃ in the CaO nanofibers to prevent CaO grain growth caused by CaCO₃ sintering. It is revealed that the sorbent CO₂ uptake capacity decreases both with an increase in the decarbonation temperature and with an increase in the CO₂ concentration in the gas flow upon carbonation, where the sorbent CO₂ uptake capacity is more sensitive to the decarbonation temperature than to the CO₂ concentration in the gaseous stream during carbonation. It is assumed that the electrospun regenerable Zr-doped CaO sorbent is effective for removing CO₂ from flue gases.