Preparation of Phosphorus-containing Porous Carbon by Direct Carbonization for Acetone Adsorption

Abstract

The surface functional groups present in activated carbon have been regarded to take on an important role in VOCs adsorption. Herein, phosphorus-containing porous carbons (PPCs) were prepared by the direct carbonization of potassium phytate and were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectrum, specific surface area and pore analysis, and X-ray photoelectron spectroscopy (XPS). The synergistic effect of phosphorous-containing functional groups and specific surface area on acetone adsorption was investigated by experiments and the underlying mechanism was studied by density functional theory (DFT) calculations. The results showed that PPCs carbonized at 900 ℃ show a high acetone capacity of 6.62 mmol/g at 18 kPa due to a high specific surface area (1060.99 m2 g-1) and desirable phosphorus content (1.32%). Furthermore, the adsorption behaviour of phosphorus-containing functional groups (C-O-P, C3-P, C3-P=O and C-P-O) was clarified by DFT calculations, focusing on the three parameters of adsorption energy, adsorption equilibrium distance and charge transfer amount. The DFT calculations verified that the affinity between the carbon substrate and acetone molecule was significantly enhanced by adding different phosphorus-containing functional groups.