Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6471647 | Electrochimica Acta | 2017 | 10 Pages |
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 â¼250Â h, involving â1.18Â ÃÂ 104Â C.cmâ2 of charge transfer at overpotentials as low as â0.2Â V vs. RHE. We find that this high-performance of bSi makes it attractive as a green solar-to-hydrogen platform.