MgO promoted by Fe2O3 and nitrate molten salt for fast and enhanced CO2 capture: Experimental and DFT investigation

作者：Gong, Fengchun; Huang, Zhen; Wei, Xiaolan; Liu, Shule; Lu, Jianfeng; Ding, Jing^*; Wang, Weilong^*

来源：SEPARATION AND PURIFICATION TECHNOLOGY, 2023, 307: 122766.

DOI：10.1016/j.seppur.2022.122766

• Carbon neutrality
• CO2 capture
• MgO
• Rapid kinetics
• Adsorpti on mechanism
• DFT calculations

Rapid and strong CO2 capture is critical in CO2 capture and utilization (CCU) techniques to mitigate global warming. Alkali molten salt (AMS) promoted-MgO sorbents with high capacity attracted attention, but their applications suffer from various limitations of low adsorption kinetics and poor stability. Here, AMS-promoted MgO sorbents corporation with Fe2O3 (Mg100-xFex-AMS(10)) were fabricated via modified methanol evaporation-induced surface precipitation for use in rapid and stable CO2 capture. Based on characterization of the sorbents, Mg98Fe2-AMS(10) showed a loose flake structure, with a large surface area and numerous exposed active sites. Therefore, Mg98Fe2-AMS(10) exhibited a strong CO2 capacity (14.86 mmolCO(2)/gsorbent at 300 degrees C) and good cyclic durability. Three kinetic models were explored, and the Avrami model provided a good prediction of the CO2 adsorption behavior, with Mg98Fe2-AMS10 exhibiting rapid adsorption kinetics. The adsorption mechanism was investigated using density functional theory (DFT) calculations. The charge transfer and bonding strengths of the surface O atoms on MgO increased, and these atoms preferentially bonded with activated CO2 (CO2 center dot-) under Fe catalysis. This study may provide insights into enhancing the CO2 capture and kinetics of MgO via combination with 3d transition metals.

• 单位
  中山大学