Boron nitride (BN) has the newly-found property of degrading recalcitrant polyfluoroalkyl substances (PFAS) under ultraviolet C (UV-C, 254 nm) irradiation. It is ineffective at longer wavelengths, though. In this study, we report the simple calcination of BN and UV-A active titanium oxide (TiO₂) creates a BN/TiO₂ composite that is more photocatalytically active than BN or TiO₂ under UV-A for perfluorooctanoic acid (PFOA). Under UV-A, BN/TiO₂ degraded PFOA ∼15× faster than TiO₂, while BN was inactive. Band diagram analysis and photocurrent response measurements indicated that BN/TiO₂ is a type-II heterojunction semiconductor, facilitating charge carrier separation. Additional experiments confirmed the importance of photogenerated holes for degrading PFOA. Outdoor experimentation under natural sunlight found BN/TiO₂ to degrade PFOA in deionized water and salt-containing water with a half-life of 1.7 h and 4.5 h, respectively. These identified photocatalytic properties of BN/TiO₂ highlight the potential for the light-driven destruction of other PFAS.

氮化硼（BN）具有在紫外线C（UV-C，254 nm）照射下降解难降解多氟烷基物质（PFAS）的新特性。但是，它在更长的波长下是无效的。在这项研究中，我们报道了 BN 和 UV-A 活性二氧化钛 (TiO ₂ ) 的简单煅烧产生了 BN/TiO ₂复合材料，该复合材料在 UV-A 下对全氟辛酸 (PFOA) 的光催化活性比 BN 或 TiO _2更高。在 UV-A 下，BN/TiO ₂降解 PFOA 的速度比 TiO ₂快约 15 倍，而 BN 是非活性的。能带图分析和光电流响应测量表明，BN/TiO ₂是一种 II 型异质结半导体，有利于载流子分离。其他实验证实了光生空穴对降解 PFOA 的重要性。自然阳光下的户外实验发现，BN/TiO ₂在去离子水和含盐水中降解 PFOA 的半衰期分别为 1.7 小时和 4.5 小时。这些确定的 BN/TiO ₂的光催化特性突出了其他 PFAS 光驱动破坏的潜力。