We first report that photoelectrochemical (PEC) performance of electrochemically hydrogenated TiO₂ nanotube arrays (TNTAs) as high-efficiency photoanodes for solar water splitting could be well tuned by designing and adjusting the phase structure and composition of TNTAs. Among various TNTAs annealed at different temperature ranging from 300 to 700 °C, well-crystallized single anatase (A) phase TNTAs-400 photoanode shows the best photoresponse properties and PEC performance due to the favorable crystallinity, grain size and tubular structures. After electrochemical hydrogenation (EH), anatase-rutile (A-R) mixed phase EH-TNTAs-600 photoanode exhibits the highest photoactivity and PEC performance for solar water splitting. Under simulated solar illumination, EH-TNTAs-600 achieves the best photoconversion efficiency of up to 1.52% and maximum H₂ generation rate of 40.4 µmol h⁻¹ cm⁻², outstripping other EH-TNTAs photoanodes. Systematic studies reveal that the signigicantly enhanced PEC performance for A-R mixed phaes EH-TNTAs-600 photoanode could be attributed to the synergy of A-R mixed phases and intentionally introduced Ti³⁺ (oxygen vacancies) which enhances the photoactivity over both UV and visible-light regions, and boosts both charge separation and transfer efficiencies. These findings provide new insight and guidelines for the construction of highly efficient TiO₂-based devices for the application of solar water splitting.

我们首先报道了电化学氢化 TiO _{2的光电化学 (PEC) 性能}通过设计和调整 TNTA 的相结构和组成，可以很好地调整纳米管阵列 (TNTA) 作为太阳能水分解的高效光阳极。在 300 至 700 °C 的不同温度下退火的各种 TNTA 中，结晶良好的单锐钛矿 (A) 相 TNTAs-400 光阳极由于良好的结晶度、晶粒尺寸和管状结构而显示出最佳的光响应特性和 PEC 性能。电化学氢化 (EH) 后，锐钛矿-金红石 (AR) 混合相 EH-TNTAs-600 光阳极表现出最高的太阳能分解水光活性和 PEC 性能。在模拟太阳光照射下，EH-TNTAs-600 实现了最高 1.52% 的最佳光转换效率和40.4 µmol h ⁻¹  cm的最大 H ₂生成率^-2，超过其他 EH-TNTAs 光电阳极。系统研究表明，AR 混合相 EH-TNTAs-600 光电阳极显着增强的 PEC 性能可归因于 AR 混合相的协同作用和有意引入的 Ti ³⁺（氧空位），从而增强了紫外线和可见光的光活性区域，并提高电荷分离和转移效率。这些发现为构建用于太阳能水分解应用的高效基于 TiO _{2的设备提供了新的见解和指导。}