In-situ construction of W₁₈O₄₉-CNT-BiOBr step-scheme material with enhanced interfacial charge separation characteristics

Environmental pollution and energy shortages significantly had affected human health and social development. Improving the photogenerated carrier separation/transfer efficiency of semiconductors remained crucial for achieving efficient photoelectric conversion and effective pollution purification. Using tungsten hexachloride as the raw material, tungsten oxide nanowires (W₁₈O₄₉) were firstly prepared by solvothermal method. Subsequently, the W₁₈O₄₉ nanowires were ultrasonically dispersed with carbon nanotubes (CNTs) in an aqueous potassium bromide solution, which was then added dropwise into acetic acid containing bismuth nitrate. By employing one-step solution-phase method, a W₁₈O₄₉-CNT-BiOBr step-scheme material with oxygen vacancy modulation was synthesized via in-situ reaction at room temperature. This W₁₈O₄₉-CNT-BiOBr with plasmonic effects demonstrated significantly enhanced solar light absorption efficiency, photoelectric response capability, and photocatalytic activity for pollutant degradation, and displayed a certain level of self-powered photoelectric response capability. Within 20 min, the degradation rate of 20 mg/L Rhodamine B (RhB) achieved approximately 99.8% with 10 mg W₁₈O₄₉-CNT-BiOBr, which was notably superior to that of pure W₁₈O₄₉ (72.9%) and BiOBr (55.8%). Further studies revealed that the separation and transport efficiency of photogenerated carriers in W₁₈O₄₉-CNT-BiOBr was significantly enhanced, which were mainly related to the construction of W₁₈O₄₉-CNT-BiOBr heterostructure, the introduction of oxygen vacancy and their synergistic effects among the components. Additionally, the superoxide radicals generated in W₁₈O₄₉-CNT-BiOBr heterostructure played a crucial role in the photocatalytic degradation of RhB.