Phase boundary construction and multi-field synergy: multifunctional applications of TiO₂ conductive coatings

Titanium dioxide (TiO₂)-based conductive coatings are promising for aerospace, marine, and energy applications because of their environmental friendliness and low cost. However, yet their practical use is hindered by high photogenerated charge recombination and poor visible-light response. Although constructing triphasic heterostructures can enhance performance, their high-temperature instability remains a critical barrier. Herein, a synergistic strategy combining Co/Ni co-doping and graphene compositing is used: lattice stress caused by ionic radius differences generates a pinning effect that stabilize the anatase/brookite/rutile triphasic heterostructure, while chemical bonding with graphene constructs multilevel conductive pathways (Ti-O-C, Co-O-C, Ni-O-C). The built-in electric field at the triphasic heterointerfaces drives directional charge separation, and the highly conductive graphene network enables efficient carrier migration from the lattice to the interface, synergistically enhancing conductivity and establishing a dual charge transport mechanism. Structural characterization and theoretical calculations confirm that this strategy effectively stabilizes the multiphase structure and constructs multilevel conductive pathways. The resulting CN-T/G coating exhibits a low resistivity of 0.23 Ω · cm (a 79.6% reduction), a protection efficiency of 91.25%, super-hydrophobicity (water contact angle of 159.25°), and photocatalytic self-cleaning ability. This work provides a feasible design strategy for creating efficient, stable, and multifunctional TiO₂-based conductive materials.