Pure and strontium carbonate nanoparticles functionalized microporous carbons with high specific surface areas derived from chitosan for CO2 adsorption

Abstract

A simple one step chemical activation involving a relatively mild chemical potassium citrate and inexpensive chitosan as a carbon source is presented for the synthesis of microporous carbons with a high specific surface area. The synthesis avoids the use of a highly corrosive and unfriendly activating agent, KOH, which is generally used for the creation of the porosity. The obtained microporous carbons display a high specific surface area which can be tuned by varying the amount of activating agent (1784–2278 m2 g−1). The optimized material exhibits a high surface area of 2278m2 g−1 and a pore volume of 1.00 cm3 g−1. As high microporosity is beneficial for CO2 adsorption, the prepared materials are employed as adsorbents for the capture of CO2. The optimized sample displays excellent CO2 uptakes at 0 °C/0.15 bar (1.1–1.8 mmol g−1) and 0 °C/1 bar (4.3–6.1 mmol g−1). The high surface area of the materials allows for high CO2 uptakes at 0 °C/30 bar (17.3–22.0 mmol g−1). The microporosity of these high surface area carbons is further decorated with strontium carbonate nanoparticles. The adsorption capacity per unit surface area is increased significantly upon the incorporation of the nanoparticles, revealing the role of the nanoparticles on the enhancement of the CO2 adsorption capacity. A similar strategy could be extended for the fabrication of a series of microporous carbons derived from biomass for many applications including CO2 capture.