Atomic-interface engineered coherent TiN/N-TiO₂ heterojunction for LSPR enhanced full-spectrum solar hydrogen production

AbstractIntegrating infrared-responsive localized surface plasmon resonance (LSPR) materials with photocatalysts shows great potential for photocatalytic water splitting into hydrogen, yet their interfacial lattice mismatch critically restricts infrared photon utilization from the LSPR component. Herein, we propose an atomic doping-guided epitaxial growth strategy to construct a coherent TiN/Nitrogen-doped-TiO₂ (TiN/N-TiO₂) heterojunction with full-spectrum absorption and a lattice-matched interface. Pre-incorporated nitrogen atoms on the TiO₂ (110) facets act as self-aligned nucleation sites, directing the covalent N-Ti-O bridging for TiN nanodomain epitaxy. This atomic-level control reduces interfacial lattice mismatch by 21%, transitioning from semi-coherent to coherent interfacial configuration. The resultant coherent architecture establishes a low-resistance carrier highway, lowering the activation energy for interfacial charge transfer by 48% and enabling efficient extraction of LSPR-generated hot carriers from TiN. The optimized TiN/N-TiO₂ achieves a hydrogen evolution rate of 6.23 mmol g−1 h−1, surpassing most reported TiO₂-based photocatalysts. This work provides atomistic insights into lattice-matching strategies for designing high-performance plasmonic photocatalytic systems, opening avenues for advanced solar fuel utilization.