Chinese Education Ministry Key Lab and International Joint Lab of Resource Chemistry, Shanghai Normal University, Shanghai 200234, P. R. China.
Environ Sci Technol. 2020 May 5;54(9):5902-5912. doi: 10.1021/acs.est.9b07757. Epub 2020 Apr 14.
Most photoelectrocatalytic (PEC) reactions are performed in the liquid phase for convenient electron transfer in an electrolyte solution. Herein, a novel PEC reactor involving a tandem combination of TiO nanorod array/fluorine-doped tin oxide (TiO-NR/FTO) working electrodes and an electrochemical auxiliary cell was constructed to drive the highly efficient PEC oxidation of indoor gas (NO). With the aid of a low bias voltage (0.3 V), the as-formed PEC reactor exhibited an 80% removal rate for oxidizing NO (500 ppb) under light irradiation, which is much higher than that of the traditional photocatalytic (PC) process. Upon being irradiated by light, the photogenerated electrons are quickly separated from the holes and transferred to the counter electrode (Pt) owing to the applied bias voltage, leaving photogenerated holes in the TiO-NR/FTO electrode for oxidizing NO molecules. Moreover, both dry and humid NO could be effectively removed by the tandem TiO-NR/FTO-based gas-phase PEC reactor, indicating that the NO molecules could also be directly oxidized by photogenerated holes in addition to hydroxyl radicals. The presence of trace amounts of water could promote the PEC oxidation of NO owing to the formation of hydroxyl radicals induced by reactions between the water and holes, which could further oxidize NO. This PEC reactor offers an energy-saving, environmentally friendly, and efficient route to treat air polluted with low concentrations of gases (NO and SO).
大多数光电催化（PEC）反应都是在液相中进行的，以便在电解质溶液中进行方便的电子转移。在此，构建了一种涉及 TiO 纳米棒阵列/掺氟氧化锡（TiO-NR/FTO）工作电极串联组合和电化学辅助电池的新型 PEC 反应器，以驱动室内气体（NO）的高效 PEC 氧化。在低偏置电压（0.3 V）的辅助下，所形成的 PEC 反应器在光照下对氧化 NO（500 ppb）的去除率达到 80%，远高于传统的光催化（PC）过程。在光照下，光生电子由于施加的偏置电压而迅速与空穴分离并转移到对电极（Pt），从而在 TiO-NR/FTO 电极中留下光生空穴来氧化 NO 分子。此外，干燥和潮湿的 NO 都可以通过串联的 TiO-NR/FTO 基气相 PEC 反应器有效去除，这表明 NO 分子也可以直接被光生空穴氧化，而不是仅仅通过羟基自由基。痕量水的存在可以通过水和空穴之间的反应诱导形成的羟基自由基来促进 NO 的 PEC 氧化，从而进一步氧化 NO。该 PEC 反应器为处理低浓度气体（NO 和 SO）污染的空气提供了一种节能、环保和高效的途径。
