One-step synthesis of flour-derived functional nanocarbons with hierarchical pores for versatile environmental applications

Abstract

In this study, we develops a one-step and scalable approach to synthesize functional carbons with a tuneable and hierarchically porous structure as well as tailored surface chemistry for environmental applications in CO 2 adsorption and carbocatalysis to remove emerging water contaminants. By pyrolyzing a mixture of wheat flour and NaHCO 3 /Na 2 CO 3 /K 2 CO 3 at 700 °C, honeycomb structured carbons (700-PC) with dominant micropores can be formed and exhibit an excellent CO 2 storage capacity of 6.8 mmol g -1 at 0 °C and ambient pressure. By including dicyandiamide in the precursors, coralloid carbon skeletons in a micro- and meso-porous texture are selectively formed in the N-doped hierarchical porous carbons (N-PCs). 800-N-PC (N-PCs prepared at 800 °C) with a high surface area of 3041 m 2 g -1 shows an enhanced capacity of 19.4 mmol g -1 at 0 °C, 10 bar. For water remediation, 800-N-PC exhibits the most efficient degradation of p-hydroxybenzoic acid (HBA) by advanced oxidation processes (AOPs), with a high reaction rate constant of 0.39 min -1 at 25 °C. In addition, 800-N-PC shows selective adsorption of HBA in a mixed solution of HBA and phenol, while both of them can be effectively degraded by the AOPs. The mechanism of adsorption and catalysis of the newly developed porous carbon is discussed.