Site‐selective Mono‐ and Bifunctionalization of Graphene Oxide: Screening Nanocatalysts for Organophosphate Degradation

Abstract

AbstractTargeted multiple functionalization is a promising tool for developing nanocatalysts for the degradation of toxic organophosphates, present in many agrochemicals and chemical warfare. Herein, we functionalized graphene oxide with two different functional groups (thiol and imidazole), focused on two distinct anchoring sites: epoxide and carboxylic acids. The mono‐ and bifunctionalized materials showed pronounced catalytic activity in the degradation of a toxic organophosphate. This was attributed to cooperative multiple catalyses by the reactive imidazole/thiol groups and neighbouring groups (carboxylate/hydroxyl) on the nanocatalyst backbone. The best nanocatalyst was monofunctionalized via epoxides, which showed the lowest degree of functionalization and highest amount of carboxylic acids. In this case, it could benefit from a bifunctional nucleophilic and general base catalysis involving the thiol and carboxylate groups, respectively. The bifunctionalization strategy via both epoxide and carboxylic acids showed to be better than the analogue bifunctionalized solely via the carboxylic acids, evidencing the importance of the spatial distribution of the anchoring sites. Overall, the functionalization strategy varies the positioning and availability of reactive groups which directly affects the catalytic outcome.