Facile Synthesis of High-Surface-Area Mesoporous MgO with Excellent High-Temperature CO₂ Adsorption Potential

Mesoporous magnesium oxide of high surface area (>350 m²/g) has been synthesized by a simple ammonia precipitation method from an aqueous magnesium nitrate solution. This material has been evaluated for CO₂ adsorption in the temperature and pressure regimes relevant to precombustion capture in an integrated gasification combined cycle scheme. CO₂ adsorption capacities were also compared with those of magnesium oxides obtained by other synthetic routes such as hydrothermal urea hydrolysis and direct thermal degradation of magnesium nitrate. Mesoporous magnesium oxide shows a CO₂ capacity at high temperatures that is comparable or even exceeds the capacity values for this class of high-temperature CO₂ adsorbents reported in the literature so far. The materials studied have been characterized by various characterization techniques like powder X-ray diffraction, surface area, pore-size distribution analysis, scanning electron microscopy, and Fourier transform infrared. A cyclic adsorption/desorption study was also carried out to understand the multicycle stability of the adsorbent for high-temperature CO₂ capacity.