Universidad Autónoma Metropolitana-Iztapalapa, Depto. de Química, Área de Catálisis, Grupo ECOCATAL, Av. San Rafael Atlixco No 186, 09340, Ciudad de México, Mexico.
Cátedra CONACyT, Universidad Autónoma Metropolitana, Grupo ECOCATAL, Av. San Rafael Atlixco No 186, 09340, Ciudad de México, Mexico.
J Environ Manage. 2021 Mar 15;282:111602. doi: 10.1016/j.jenvman.2020.111602. Epub 2021 Jan 22.
Photocatalytic oxidation of arsenite (As(III)) to arsenate (As(V)) was studied in aqueous solution using a series of WO/TiO semiconductors readily synthesized through sol-gel method with WO content in the range of 1-5 wt%. The resulting materials showed enhanced photocatalytic activity towards As(III) photo-oxidation compared to their individual counterparts under UV radiation. The amount of As(III) and As(V) species in the irradiated solution was determined using the molybdenum blue method. The efficiency of photoinduced carriers separation was further affirmed by electrical impedance spectroscopy (EIS) and photocurrent tests. The maximum catalytic efficiency was observed when the binary oxide 3%WO/TiO (TW3) was used, reaching a 99% conversion of As(III) to As(V) within the first 25 min under UV irradiation. The enhanced photocatalytic performance of the heterostructures could be explained as consequent to an improved charge separation due to the migration of photoproduced holes in TW3 photocatalyst. Based on the electric band structure of WO and TiO, a reasonable mechanism for the photo-oxidation of As(III) over TW3 novel catalyst has been proposed.
采用溶胶-凝胶法制备了一系列 WO/TiO 半导体，WO 含量在 1-5wt%范围内，研究了其在水溶液中对亚砷酸盐（As(III)）光催化氧化为砷酸盐（As(V)）的作用。与单独的 WO 和 TiO 相比，这些材料在紫外光辐射下对 As(III)光氧化具有更高的光催化活性。用钼蓝法测定了辐照溶液中 As(III)和 As(V)的含量。通过交流阻抗谱（EIS）和光电流测试进一步证实了光生载流子分离的效率。当使用二元氧化物 3%WO/TiO（TW3）时，观察到最大的催化效率，在紫外光照射下最初的 25 分钟内，As(III)的转化率达到 99%。TW3 光催化剂中光生空穴的迁移导致载流子分离得到改善，从而解释了 TW3 异质结构光催化性能的增强。根据 WO 和 TiO 的能带结构，提出了一种合理的 TW3 新型催化剂光氧化 As(III)的反应机理。
