A novel adsorptive and photocatalytic system for dye degradation using ZIF-8 derived carbon (ZIF-C)-modified graphene oxide nanosheets

Abstract

BackgroundAerogels have attracted widespread interest in adsorption and photocatalysis. The effect of single aerogel material cannot meet the demand and we can enhance the adsorption and photocatalysis efficiency via adding other materials such as ZIF-8 and graphene oxide (GO). MethodsWe developed an adsorptive and photocatalytic system of ZIF-GO/CCA using a cellulose-based carbon aerogel (CCA) for the fabrication of GO nanosheets modified with ZIF-8-derived carbon (ZIF-C), followed by pyrolysis. The characteristics were evaluated using SEM, HRTEM, BET, XRD, XPS, UV–vis DRS, ESR, PL, EIS and LC-MS analysis. Significant findingsCCA exhibit hierarchical porosity and conductive network, which provides abundant active sites for dye adsorption and degradation. ZnO and g-C3N4 were formed after the incorporation of ZIF-C into GO to, promote charge separation. In the presence of 1ZIF-GO/CCA and at an initial concentration of 300 mg·L−1 MG, the removal of MG exceeded 96%. The removal capacity reached 1152 mg·g−1 after adsorption-photocatalysis for 120 min. 1ZIF-GO/CCA showed the largest specific surface area (375.059 m2·g−1). GO served as an excellent electron accepter to enable fast electron transfer from the ZIF-C to the conduction band of GO. The narrower bandgap (2.06 eV) and lower resistance during charge transfer promoted the separation of e−/h+ and contributed to the higher photocatalytic activity of ZIF-GO/CCA. Further, ZIF-GO/CCA showed increased recyclability. The plausible photocatalytic mechanism for the 1ZIF-GO/CCA was discussed.