Construction of W18O49/ZnTiO3 Z-Scheme heterojunction with rich oxygen vacancies and LSPR effect for enhanced photocatalytic H2 evolution

Abstract

Photocatalytic water splitting is widely regarded as a clean and sustainable approach for H₂ evolution, offering great potential to address the energy crisis and reduce environmental pollution. However, the practical application of photocatalysts is hindered by low utilization of photogenerated carriers and rapid electron-hole recombination. To overcome these challenges, Z-scheme W₁₈O₄₉/ZnTiO₃ heterojunctions nanoparticles are successfully synthesized via a solvothermal method and systematically investigated their photocatalytic performance for H₂ evolution. Structural characterization reveals intimate interfacial contact and a stable Z-scheme electron transfer pathway between W₁₈O₄₉ and ZnTiO₃. The abundant oxygen vacancies in W₁₈O₄₉ modulate the electronic structure and trigger a strong localized surface plasmon resonance (LSPR) effect, which significantly enhances visible and near-infrared light absorption. The LSPR effect generates hot electrons that can directly transfer to ZnTiO₃, increasing the number of photogenerated electrons available for H₂ evolution. Photoelectrochemical analysis confirms that the built-in electric field of the Z-scheme structure facilitates efficient charge separation and migration. Under simulated sunlight, the WZn-2 composite sample exhibits a high H₂ evolution rate of 1.73 mmol g⁻¹ h⁻¹, outperforming the W₁₈O₄₉ and ZnTiO₃ original sample. This not only provides new insights into the design of high-performance photocatalytic materials, but also offers potential applications in clean energy development and utilization.