Photon absorption, charge separation and transportation, and charge-induced reactions at the active sites are the main crucial factors involved in the photoelectrochemical (PEC) water splitting. Herein, a combination of black phosphorus quantum dot (BPQD) sensitization and defect engineering strategies is employed to optimize the PEC performance of one-dimensional TiO₂ nanotube array (NTA) photoanodes. The as-prepared TiO_2–x/BP electrode exhibits a strong photocurrent density under simulated solar light irradiation, which is almost ∼3 times higher than that of bare TiO₂. Specifically, the photocurrent increment of TiO_2–x/BP is even larger than the sum of TiO_2–x and TiO₂/BP, verifying the synergistic effect of oxygen vacancies and BPQD sensitization. The maximum photoconversion efficiency of TiO_2–x/BP is as high as 0.35%, while the value of TiO₂ NTAs is calculated to be 0.13%. The results reveal that oxygen vacancies and BPQDs in the TiO_2–x/BP composite not only facilitate the charge separation and transportation but also enhance the activity and quantity of reactive sites for water oxidation. The present strategy might open new routes to develop high-performance photoelectrodes for water splitting.

中文翻译：

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黑色磷量子点敏化的TiO ₂纳米管阵列，具有丰富的氧空位，可以有效地进行光电化学水分解

光子在活性位点的吸收，电荷的分离和运输以及电荷诱导的反应是光电化学（PEC）水分解的主要关键因素。本文中，结合使用黑磷量子点（BPQD）敏化和缺陷工程策略来优化一维TiO ₂纳米管阵列（NTA）光电阳极的PEC性能。所制备的TiO ₂ – _x / BP电极在模拟太阳光照射下表现出很强的光电流密度，几乎是裸TiO _2的约3倍。具体地说，TiO _{2– x} / BP的光电流增量甚至大于TiO _{2– x}和TiO之和₂ / BP，验证氧空位和BPQD致敏的协同作用。TiO _{2– x} / BP的最大光转换效率高达0.35％，而TiO ₂ NTAs的值计算为0.13％。结果表明，TiO _{2– x} / BP复合材料中的氧空位和BPQDs不仅促进了电荷的分离和运输，而且还增强了水氧化反应的活性和活性位点的数量。当前的策略可能会开辟新的途径来开发用于水分解的高性能光电极。