Novel graphitic carbon nitride nanoparticles (NPs)-wrapped TiO₂ nanotube arrays (NTAs) (g-C₃N₄/TiO₂) were fabricated by a two-step method including an electrochemical anodization technique followed by impregnation under vacuum using urea as precursor. The as-prepared photoelectrode exhibited outstanding photoelectric properties and excellent photelectrocatalytic (PEC) performance for the degradation of phenol under stimulated solar light, which was due to the enhanced light absorption property and improved charge separation efficiency. The introduction of g-C₃N₄ NPs strongly decreased the charge transfer resistance and boosted the charge separation efficiency of TiO₂. The optimum ratio of the g-C₃N₄/TiO₂ yielded a pronounced 4.18-fold higher photocurrent density than TiO₂. Besides, the combination of g-C₃N₄ NPs could negatively shift for the flat band potential of TiO₂, resulting in an enhanced reduction property for the photoelectrocatalytic degradation of organic pollutants. The PEC process for the degradation of phenol over g-C₃N₄/TiO₂ was much higher than the sum of photocatalytic (PC) and electrocatalytic (EC) processes indicating that a photoelectric synergy was achieved on the as-prepared photoelectrode and resulting in an improved PEC performance for the composite photoelectrode.

中文翻译：

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包裹有gC ₃ N ₄纳米粒子的高度有序的TiO ₂纳米管阵列，用于有效的电荷分离和增加的苯酚的光电催化降解

通过包括电化学阳极氧化技术的两步法，然后使用尿素作为前体在真空中浸渍，制备了新颖的石墨碳氮化物纳米颗粒（NPs）包裹的TiO ₂纳米管阵列（NTA）（gC ₃ N ₄ / TiO ₂）。所制备的光电极显示出优异的光电性能和优异的光刺激性，在刺激的太阳光下苯酚的降解具有光电子催化性能，这归因于增强的光吸收性能和提高的电荷分离效率。gC ₃ N ₄ NPs的引入极大地降低了电荷转移阻力，并提高了TiO ₂的电荷分离效率。gC ₃ N ₄ / TiO ₂的最佳比例产生比TiO ₂高出4.18倍的光电流密度。此外，gC ₃ N ₄ NPs的组合可能使TiO ₂的平带电势发生负移，从而增强了对有机污染物的光电催化降解的还原性能。PEC在gC ₃ N ₄ / TiO _2上降解苯酚的方法 远高于光催化（PC）和电催化（EC）过程的总和，表明在制备的光电极上实现了光电协同作用，并改善了复合光电极的PEC性能。