Prediction of Silicon Nanowires as Photocatalysts for Water Splitting: Band Structures Calculated Using Density Functional Theory

Hydrogen as an efficient energy carrier is an environmentally benign fuel of the future. Solar-powered water splitting, using semiconductor photocatalysts, is an efficient generation method of hydrogen where excellent photocatalysts are key factors. In this work, we investigate silicon nanowires (SiNWs) as photocatalysts for the water splitting. By utilizing density functional theory calculations, we demonstrated that SiNWs terminated with suitable H and Cl surface coverage should be a promising photocatalyst for this purpose. The interaction between Cl-3 p and surface Si-3 p states of SiNWs leads to suitable reducing and oxidizing powers simultaneously while the separation of HOMO and LUMO of SiNWs prevents the electron−hole recombination.