A highly efficient Bi₂O₃-TiO₂ composite, prepared by a facile hydrothermal method, can be used for the removal of heavy metal Pb(II) and refractory organic dibutyl phthalate (DBP) from wastewater under visible light irradiation. The photo-induced electrons and holes separately transfer to different locations on the composite, resulting in different photocatalytic reaction sites for the refractory organic oxidation and the heavy metal reduction. This separation in space, thereby greatly improves the photocatalytic efficiency of both reactions. The energy level adjustment caused by Fermi levels matching at the n–p heterojunction, resulted in the Pb(II) being reduced to Pb(0) on the Bi₂O₃-TiO₂ composite in visible light in both the Pb(II)-only and Pb(II)-DBP mixed systems. In contrast, no reduction was observed in visible light using only a Bi₂O₃ or TiO₂ catalyst. Furthermore, the presence of refractory organic DBP in the system significantly increased the removal of Pb(II) while the presence of the more easily degradable phenol increased it to a lesser extent. These results indicate that coupling the reduction rate of heavy metals and the oxidation rate of organics can efficiently enhance the photocatalytic activity of the entire system.

通过简便的水热法制备的高效Bi ₂ O ₃ -TiO ₂复合材料可用于在可见光照射下从废水中去除重金属Pb（II）和难熔有机邻苯二甲酸二丁酯（DBP）。光诱导的电子和空穴分别转移到复合材料上的不同位置，从而导致用于难降解有机物氧化和重金属还原的光催化反应位置不同。这种空间上的分隔，从而大大提高了两个反应的光催化效率。在n–p异质结处由费米能级匹配引起的能级调整，导致Bi ₂ O ₃ -TiO ₂上的Pb（II）还原为Pb（0）在仅Pb（II）和Pb（II）-DBP混合系统中的可见光中合成。相反，仅使用Bi ₂ O ₃或TiO ₂催化剂在可见光下未观察到还原。此外，系统中难熔有机DBP的存在显着提高了Pb（II）的去除率，而更易降解的苯酚的存在则将Pb（II）的去除程度降低了。这些结果表明，结合重金属的还原速率和有机物的氧化速率可以有效地增强整个系统的光催化活性。