Flake-like tea-leaf-templated magnesium oxide for carbon dioxide adsorption

Abstract

Flake-like mesoporous magnesium oxide (MgO-TLT) was prepared using a bio-templating method with tea leaves (TLTs) as the template. MgO-TLT exhibited smaller crystallites (7.52 nm) than MgO prepared using the thermal decomposition method (22.52 nm). These smaller crystallites led to more structural defects in the adsorbent and a high basic site density; consequently, MgO-TLT exhibited a high CO2-uptake capacity of 3.17 mmol/g, which is 12-times higher than that of MgO-TD at 1 atm and 300 K, despite its low surface area. Furthermore, based on its low surface area and high uptake capacity, MgO-TLT has an uptake capacity per surface area that is more than 15-times higher than that of MgO-TD, which supports the hypothesis that MgO-TLT possesses more surface defect sites that promote the attachment of CO2. This study revealed that TLT is a promising template for use in the bio-templating syntheses of MgO adsorbents with high surface reactivities and enhanced CO2-uptake capacities.