Fabrication of the hierarchical structure photocathode by structuring the surface nanopores on Si nanowires standing on p-Si wafer for the effective photoelectrochemical reduction of Cr(VI) in the aqueous solution
Fabrication of the hierarchical structure photocathode by structuring the surface nanopores on Si nanowires standing on p-Si wafer for the effective photoelectrochemical reduction of Cr(VI) in the aqueous solution
复制标题
通过在 p-Si 晶片上的 Si 纳米线上构造表面纳米孔来制造分级结构光电阴极，以有效光电化学还原水溶液中的 Cr(VI)
DOI：
10.1016/j.seppur.2016.10.031
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发表时间：
2017
影响因子：
8.6
通讯作者：
Chen Shuo
中科院分区：
文献类型：
--
作者：
Wu Shuai;Yu Hongtao;Lu Na;Quan Xie;Chen Shuo
本文报道了一种通过在Si纳米材料（以直径约100 nm的Si纳米线阵列（SiNW）为代表）表面构造小于10 nm的纳米孔来抑制其氧化钝化的方法。采用金属辅助化学蚀刻法制备了SiNW阵列。经过30min的刻蚀后，SiNW表面形成纳米孔，并且随着刻蚀时间的延长，纳米孔的数量增加。由于纳米孔的产生，光学反射减弱。对蚀刻30min、60min和90min后制备的样品进行了电化学性能评价。刻蚀60 min的样品显示出最高且稳定的光电流，并用于光电催化测试。具有纳米孔的SiNW比具有纳米孔的SiNW表现出明显的光电催化稳定性。纳米孔SiNW还原Cr（VI）的动力学常数为0.081 min−1，是纳米孔SiNW还原（0.045 cm−1）的1.8倍，经过3次重复实验后仍保持在0.080 min−1以上。这些结果表明，在SiNW表面构建表面纳米孔是实现在水溶液中使用Si材料作为光电极的有效途径。
Herein, we reported a method to inhibit the oxidation passivation of Si nanomaterials (taking Si nanowire array (SiNW, about 100 nm of diameter) as a representative) via structuring nanopores (less than 10 nm) on their surface. SiNW array was prepared through metal-assisted chemical etching. After 30 min of etching, nanopores were formed on the surface of SiNW and the amount of nanopores increased with the prolonging of the etching duration. Due to the generation of the nanopores, the decrease of optical reflection was observed. The photoelectrochemical performance of samples prepared after 30, 60 and 90 min etching were evaluated. The sample etched for 60 min displayed the highest and stable photocurrent and was used in the photoelectrocatalytic testing. The SiNW with nanopores exhibited significant photoelectrocatalytic stability than that of SiNW. The kinetic constant of Cr(VI) reduction over SiNW with nanopores was 0.081 min−1, which was 1.8 times as much as that over SiNW (0.045 cm−1) and maintained above 0.080 min−1after three repeated experimental runs. These results demonstrate that constructing surface nanopores on the surface of SiNW is an effective approach to realize the use of Si materials as photoelectrodes in the aqueous solution.