Preparing microporous carbon from solid organic salt precursors using in situ templating and a fixed-bed reactor

Carbon-based adsorbents contain high internal surface area, desirable pore structure, and controlled surface functionalities, making them effective for gas purification, separation, and storage. This research describes a simple technique for preparing porous carbons from solid organic salt precursors and examines the physical and chemical properties of these materials. A two-step (i.e., pyrolysis and washing), fixed-bed system is used to synthesize high surface area carbon from solid organic salt precursors. The organic salts are pyrolyzed to remove reactive leaving groups (i.e., H₂O, CO, CO ₂, and/or HCl). The remaining carbon atoms network around an in situ, solid salt template to develop internal porosity. Post-pyrolysis washing dissolves the salt template to isolate the remaining porous carbon products. Increased microporosity and surface area occur with this technique when compared to carbons prepared by a similar spray pyrolysis approach. Carbons prepared with the two-step method are >70% microporous and up to 740 m²/g. Surface oxygen content of these carbons increases from 5% to 25% with decreasing pyrolysis temperature. This technique provides control over surface area and oxygen content of the carbon products, an important step towards tailoring the carbon's adsorption capacity for specific applications.