Abstract
Nanostructured black Si materials prepared by metal-assisted wet chemical etching (MaCE) using HF to drive the nanostructuring, have emerged as excellent light-harvesting materials for solar water splitting. Recently, their remarkable solar-to-hydrogen conversion capability was attributed to their surface oxidation mechanism. However, the same mechanism inhibits the interfacial kinetics within hours, and therefore they are deemed not suitable for a fully-functional hydrogen generating cell. Herein, we investigate the performance and interfacial kinetics of solar-to-hydrogen fuel conversion on black Si photocathodes that, for the first time, are free of any metal catalysts. We developed a near 100% metal-free Si interface by a HF-free etching approach. Systematic analysis and optimization of the nanostructure morphology and photoelectrochemical procedures supported continuous photoelectrochemical hydrogen generation for ∼250 h, involving −1.18 × 104 C.cm−2 of charge transfer at overpotentials as low as −0.2 V vs. RHE. We find that this high-performance of bSi makes it attractive as a green solar-to-hydrogen platform.
Original language | English |
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Pages (from-to) | 453-462 |
Number of pages | 10 |
Journal | Electrochimica Acta |
Volume | 235 |
DOIs | |
Publication status | Published - 1 May 2017 |
Keywords
- Black silicon
- Metal-free
- Oxidized black Si
- Photocathodes
- SiNW catalysts
Equipment
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Centre for Electron Microscopy (MCEM)
Peter Miller (Manager)
Office of the Vice-Provost (Research and Research Infrastructure)Facility/equipment: Facility