Newly synthesized nanocrystalline TiO₂ mixed-phase photocatalysts are shown to surpass in Selenium (VI) reduction effectiveness the commercial P25 nanoTiO₂ photocatalyst Heterojunctioned rutile (63 %)/brookite (37 %) (designated as R_/b) nanoTiO₂ is found to be the most effective photocatalyst achieving 95 % photo-assisted reductive deposition vs. 25 % only by the benchmark P25 composed of anatase (80 %) and rutile (A_/r). This is attained at very high photocharge utilization with at least 5-fold less formic acid as hole scavenger. The superior performance of R_/b is attributed to a favorable band alignment at the heterojunction and its 1D-dominated nanocrystal orientation enabling efficient co-adsorption and enhanced charge separation. The deposition of elemental Se further “auto-catalyzes” the photocatalytic process by enabling visible light activity with simultaneous suppression of charge recombination. In-depth probing of the R_/b photocatalyst after selenium removal provides evidence of a 2-step mechanism involving (a) reductive adsorption of Se(VI)_aq → Se(IV)_surf with the participation of co-adsorbed formate and Ti³⁺ defects, and photoreduction of Se(IV)_surf → Se(0)_surf.

新合成的纳米晶 TiO _{2混合相光催化剂在}硒₍ VI )还原效率上优于商业 P25纳米_{TiO 2}光催化剂是实现 95% 光辅助还原沉积的最有效光催化剂，而仅由锐钛矿 (80%) 和金红石 ( A _/r ) 组成的基准 P25 为 25%。这是在非常高的光电荷利用率下获得的，甲酸作为空穴清除剂至少要少 5 倍。R _/b的优越性能归因于异质结处有利的能带排列及其一维主导的纳米晶体取向，从而实现了有效的共吸附和增强的电荷分离。元素 Se 的沉积通过使可见光活性同时抑制电荷复合来进一步“自动催化”光催化过程。去除硒后对R _/b光催化剂的深入探测提供了两步机制的证据，包括 (a) Se(VI) _aq  → Se(IV) _surf的还原吸附，同时共吸附甲酸盐和 Ti ^{3 +}缺陷，以及 Se(IV) _surf  → Se(0) _surf的光还原。