Physical and chemical activation of reduced graphene oxide for enhanced adsorption and catalytic oxidation

Abstract

Physical and chemical activation of reduced graphene oxide (RGO) using different reagents, CO₂, ZnCl₂ and CO₂/ZnCl₂, to obtain highly porous and metal-free carbonaceous materials was carried out and their adsorption and catalytic behavior were investigated. Physical activation using CO₂ was proved to be much more effective than chemical ZnCl₂ activation, and increased the specific surface area (SSA) of RGO from ∼200 to higher than 600 m² g⁻¹. Methylene blue (MB) was then used to evaluate the adsorption and catalytic activity of the activated RGO (A-RGO) materials with peroxymonosulfate (PMS) as an oxidant. It was found that the SSA and oxygen containing groups are two important factors determining the adsorptive and catalytic performance of the A-RGO materials. RGO by physicochemical CO₂/ZnCl₂ activation presented the best adsorption and RGO by physical CO₂ activation exhibited the highest catalytic degradation of MB.