正负电荷关联转移促进的光催化低浓度苯酚矿化

Photocatalytic mineralization of low concentration phenol facilitated by transfer of positive and negative charges correlation

光催化矿化难降解污染物(如苯酚)需要羟基自由基(·OH)进行开环反应。本研究通过Al掺杂削弱了TiO_(2)表面对氧物种的吸附,有效促进光致·OH的生成。同时,Al元素还能降低TiO_(2)的导带能级,继而降低半导体-助催化剂界面电子转移势垒而促进还原半反应。由于正负电荷的强关联性,还原半反应中电子的快速转移可提高半导体内空穴浓度,加快·OH的生成。此外,通过将催化剂固定在反应器的光入射内壁,还能避免由污染物竞争光吸收所引起的光子损失。基于这些优点,有望实现废水中低浓度苯酚的高效光催化矿化。

Photocatalytic mineralization of recalcitrant contaminants such as phenol requires hydroxyl radicals(·OH)for ring-opening reactions.Here,we weaken the adsorption of oxygen species on TiO_(2) surface by Al doping,which can effectively promote the photoinduced·OH generation.Besides,Al doping can downshift the conduction band of TiO2.The resulted potential barrier lowering can promote semiconductor-cocatalyst interfacial electron transfer for the reduction half-reaction.Due to the strong correlation between positive and negative charges,the rapid transfer of electrons in the reduction half-reaction can also increase the concentration of holes in the semiconductor and promote the generation of·OH.By immobilizing the photocatalyst on the light-incident inner wall of the reactor,it can avoid the competitive light absorption by the contaminant.By these virtues,efficient photocatalytic mineralization of low-concentration phenol in wastewater can be realized.