Graphene-Bridged Multicrystalline TiO2 Networks: Bimetallic Pinning Enhanced Electrochemical Performance.

Abstract

Titanium dioxide (TiO₂) three-phase heterojunctions are promising for conductive functional materials due to their gradient band structure. This study synthesizes a Ca²⁺ and Zn²⁺ co-doped TiO₂/graphene composite (Ca-Zn-T/G) via a hydrothermal method within a polyoxide metal salt (POM)-assisted system. The Ca²⁺ and Zn²⁺radius difference is utilized to introduce local periodic tensile stresses inside the lattice to form a pinned-point stabilized TiO2three-phase heterostructure. With the three-phase energy band cascade effect, the band gap is effectively shortened, and the internal directional electron transfer path is established. At the same time, the interfacial multiple electron transfer channels (Ti─O─C, Ca─O─C, Zn─O─C) are constructed with graphene, which synergistically form the internal and external double electric field mechanism to efficiently enhance the overall conductivity of the material. Experiments demonstrate that the Ca-Zn-T/G composite exhibits excellent corrosion resistance, hydrophobicity, and dispersion. This study presents an innovative strategy for developing novel titanium-based composites with high conductivity, dynamic stability, and tunable functionality, highlighting their broad application potential in energy storage and anti-corrosion coatings.