Decoration of Si-nanowires-grafted Si micropillar array with Ag nanoparticles for photoelectrocatalytic dechlorination of 4-chlorophenol
Decoration of Si-nanowires-grafted Si micropillar array with Ag nanoparticles for photoelectrocatalytic dechlorination of 4-chlorophenol
复制标题
Ag纳米粒子修饰硅纳米线接枝硅微柱阵列用于4-氯苯酚光电催化脱氯
作者：
Yu H.;Fan F.;Wu S.;Zhang H.;Lu N.;Quan X.;Chen S.;Li H.
在水溶液中使用Si材料作为光电极从根本上需要抑制绝缘SiO2层的形成以及促进光生空穴和电子从Si内部转移到固液界面。为了满足这些要求，制备了具有分级结构和Si纳米线站立在Si微柱阵列（SiNW/SiMP）表面的Si材料，以促进光生载流子向固液界面的转移。通过在SiNW/SiMP表面沉积Ag纳米颗粒来修饰SiNW/SiMP（Ag/SiNW/SiMP），通过阻止SiNW/SiMP与水的接触来成功地抑制SiO2的生成。原始的SiNW/SiMP光电阴极表现出增强的光电化学活性，在−1 V（vs. SCE）下的光电流约为−31 mA cm−2，比SiMP的光电流大一个数量级;然而，光电流随着光照时间的延长而衰减。相比之下，Ag/SiNW/SiMP光电阴极在10个循环的CV测试中在−1 V（vs. SCE）下显示出约−37.5 mA cm−2的稳定光电流，比原始SiNW/SiMP高21%。Ag/SiNW/SiMP光电阴极对4-氯苯酚（4-CP）具有良好的光电催化脱氯活性。20 min后，4-CP（初始浓度为10 mg L−1）的降解率超过95%，分别是SiMP和SiNW/SiMP的3倍和1.1倍。连续6次实验结果验证了该方法的良好重现性。
Use of Si materials as photoelectrodes in aqueous solutions is fundamentally required to inhibit the formation of an insulating SiO2 layer as well as promote the transfer of photogenerated holes and electrons from the interior of Si to the solid–liquid interface. In order to meet these requirements, an Si material, with hierarchical structure and Si nanowires standing on the surface of Si micropillar array (SiNW/SiMP), was prepared for facilitating the transfer of photogenerated carriers to the solid–liquid interface. Decoration of SiNW/SiMP by Ag nanoparticles (Ag/SiNW/SiMP) via depositing Ag nanoparticles on the surface of SiNW/SiMP successfully restrained the generation of SiO2 through preventing the contact of SiNW/SiMP with water. Pristine SiNW/SiMP photocathode exhibited enhanced photoelectrochemical activity with a photocurrent of approximately −31 mA cm−2 at −1 V (vs. SCE), which was about one order of magnitude larger than that of SiMP; however, the photocurrent decayed with prolonged illumination. By comparison, Ag/SiNW/SiMP photocathode exhibited stable photocurrent of approximately −37.5 mA cm−2 at −1 V (vs. SCE) during 10 cycles of CV testing, which was 21% higher than that of the pristine SiNW/SiMP. Ag/SiNW/SiMP photocathode exhibited excellent photoelectrocatalytic activity towards dechlorination of 4-chlorophenol (4-CP). Over 95% of 4-CP (initial concentration of 10 mg L−1) was rapidly degradaded after 20 min, which were 3 and 1.1 times higher than those of the SiMP and SiNW/SiMP. The good reproducibility was verified by the results of six consecutive experiments.