Hierarchical Structure Superlattice P₂Mo₁₈/MoS₂@C Nanocomposites: A Kind of Efficient Counter Electrode Materials for Dye-Sensitized Solar Cells

A novel type of hierarchical nanomaterial nanoflower-like superlattice P2Mo18/MoS2@C consisting of a superlattice polyoxometalate/MoS2 heterojunction coating on the surface of C nanoparticles is successfully designed and prepared by a facile step-by-step approach for the first time. The formation of superlattice P2Mo18 successfully achieved highly dispersive and small-sized polyoxometalate nanoparticles. In addition, this nanomaterial not only contains the structural advantages of a superlattice, heterojunction, and hierarchical structure but also the compositional advantages of excellent redox performance of P2Mo18, the high specific surface area and electrocatalytic activity of 2D MoS2, and the great conductivity of C nanoparticles. N2 adsorption–desorption isotherms and electrochemical tests indicate that the P2Mo18/MoS2@C nanomaterial shows a high specific surface area (174.2 m2 g–1) to provide more active sites, good electric conductivity for rapid charge transfer, and an excellent catalytic property for I3– reduction in dye-sensitized solar cells (DSSCs). The photoelectric conversion efficiency of the DSSCs using P2Mo18/MoS2@C as counter electrode reaches 8.85% and is better than that of the Pt electrode, which is attribute to the highly synergistic interactions between superlattice P2Mo18/MoS2 heterojunction and C nanoparticles. Superlattice structures with tailored electronic, catalytic, and higher electronic mobility have been proposed as a new idea for the development of polyoxometalate nanomaterials, and the reasonable selection and design of hierarchical nanostructures are an effective strategy to obtain advanced solar cell electrode materials.