Highly ordered 2D honeycomb polyoxometalate clusterphene for efficient photocatalytic degradation of organic pollutants: Mechanism, pathways, and toxicity evaluation

Abstract

Self-assembled nanomaterials have aroused enormous interest owing to their enhanced physicochemical properties as compared to monomers. Herein, two-dimensional Nd-based polyoxometalate clusterphene (Nd-POMCene) with a highly ordered honeycomb structure is synthesized by self-assembly, which is demonstrated with efficient photocatalytic degradation performance towards organic dyes, such as Rhodamine B (RhB), methylene blue, and crystal violet. Especially, RhB can be totally photodegraded by Nd-POMCene under the simulated sunlight within 1 h while a degraded efficiency of 97.50 % can be achieved under natural light within 2 h. As proved by the density functional theory results, the highly ordered structure of POMCene is beneficial for enhancing photocatalytic performance associated with the improved separation/transmission of photogenerated electron/hole pairs and large-scale electron delocalization. The mechanism study provides compelling evidence to demonstrate that all of holes, hydroxyl radicals, and superoxide radicals chemically account for the efficient photodegradation by Nd-POMCene. Finally, it is verified that there is much less toxicity in the degradation products of RhB.