Incorporation of amide functional groups to graphene oxide during the photocatalytic degradation of free cyanide

Pristine graphene oxide (GO) prepared by a conventional method (Hummers) showed to be a promising photocatalyst for the degradation of free cyanide (CN-) in aqueous solution. High conversion of cyanide was found (ca. 80%), revealing that the main by-product was amide species (C center dot ONH2) linked to GO, and a minimal amount was cyanate (CNO-) by-product in solution. Our results, supported by FTIR and Raman characterization, explain GO direct functionalization by the amide species formed during the cyanide photocatalytic oxidation. This finding could provide a new way to perform immediate GO functionaliza-tion through photocatalytic reactions and its use in other applications (e.g., CO2 adsorption). (C) 2020 Elsevier B.V. All rights reserved.