Synthesis of Hierarchical FeWO4 Architectures with {100}-Faceted Nanosheet Assemblies as a Robust Biomimetic Catalyst

Surface structure is of special significance to the heterogeneous catalysis, because catalysis is primarily a surface phenomenon. Therefore, a comprehensive understanding of the relationship between the catalytic activity and surface structure is of great importance. Herein, hierarchical FeWO4 architectures assembled by {100}-faceted nanosheets have been successfully synthesized by a facile one-pot solvothermal method and employed as a novel biomimetic catalyst mimicking enzyme for the first time. Due to the large density of terminal iron atoms per unit surface area on the {100} facet, the FeWO4 architectures exhibited excellent peroxidase-like activity for the catalytic oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue color reaction in the presence of H2O2. Using the FeWO4 architectures as peroxidase mimetics, a colorimetric sensor for H2O2 was developed, which provided good response toward H2O2 concentration over a range from 0.95 to 66.7 mu M with a detection limit of 0.28 mu M. The proposed colorimetric method can be further extended for the sensitive detection of glucose by coupling with glucose oxidase (GOx). The limit of detection for glucose was determined to be as low as 0.67 mu M and the linear range was from 4 to 60 mu M. It is believed that these findings are useful in understanding the peroxidase-like activity of catalysts with facet exposure and suggest a new strategy to pursue for highly active peroxidase-like catalysts.