A TiO₂/UV photocatalytic process generates various reactive species via different oxidation and reduction routes and thus the contribution of such reactive species to the decomposition of organic chemicals in water has been unclear. In this study, decomposition of acetylsalicylic acid (ASA) as a probe was performed to find the specific role of charge carriers (e_cb- and h_vb⁺) and primary active species (such as ^•O₂-, ^•OH, ^•HO_2, and H₂O₂). Differential pulse voltammetry (DPV) was introduced as an in-situ fast electrochemical method to identify produced intermediates. The study revealed that hydroxyl radicals (^•OH) produced by reduction of oxygen with e_cb- and subsequent primary reactions (reduction pathway) play the major role in the photocatalytic decomposition of ASA, in comparison to direct oxidation of OH- or ASA by h_vb⁺ (oxidation pathway). The in-situ DPV analysis probed that sequential ^•OH addition to the ASA aromatic ring is the favorable oxidation mechanism.

TiO ₂ / UV光催化过程通过不同的氧化和还原途径产生各种反应性物质，因此尚不清楚这种反应性物质对水中有机化学物的分解的贡献。在这项研究中，以乙酰水杨酸（ASA）为探针进行分解，以发现电荷载体（e _cb-和h _vb ⁺）和主要活性物质（例如^• O _2-，^• OH，^• HO ）的特定作用₂和H ₂ O ₂）。引入差动脉冲伏安法（DPV）作为原位快速电化学方法来鉴定产生的中间体。研究表明，与OH直接将OH-或ASA氧化后，通过e _cb-还原氧和随后的主要反应（还原途径）产生的羟基自由基（^• OH）在ASA的光催化分解中起主要作用。_vb ⁺（氧化途径）。原位分析DPV探测该顺序^• OH除ASA芳环是有利的氧化机理。