Highly active and enhanced photocatalytic silicon nanowire arrays.

Nanoporous and nonporous three-dimensional silicon nanowire arrays (SiNWAs) prepared with metal-assisted chemical etching method were investigated as photocatalysts in dye photodegradation systematically. In comparison with nonporous SiNWAs, nanoporous SiNWAs have higher surface area, larger pore volume, stronger light absorption and better photocatalytic activity. After the HF-treatment, the photocatalytic activity of all kinds of SiNWAs increased significantly and the nanoporous SiNWAs showed excellent stability. The photocatalytic activity of different types of SiNWAs with hydrogen surface termination can be recovered by HF treatment. This study also reveal that the hydrogen terminated surfaces on silicon nanowires (SiNWs) enhance the performance of SiNWAs by increasing their photocatalytic activity.