Metal-Free Black Silicon for Solar-powered Hydrogen Generation

By Halima, Ahmed F.; Zhang, Xinyi; MacFarlane, Douglas R.
Published in Electrochimica Acta NULL 2017

Abstract

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 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

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