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Inverted Pyramid Textured p‑Silicon Covered with Co2P as an Efficient and Stable Solar Hydrogen Evolution Photocathode
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posted on 2019-06-24, 00:00 authored by Sitaramanjaneva
Mouli Thalluri, Bin Wei, Katharina Welter, Rajesh Thomas, Vladimir Smirnov, Liang Qiao, Zhongchang Wang, Friedhelm Finger, Lifeng LiuSilicon (Si) has
been investigated as a promising photoelectrode
material for use in photoelectrochemical water splitting. However,
development of Si photocathodes that can operate at a high photocurrent
density for solar-driven hydrogen production with long-term stability
remains challenging. Herein, we report the fabrication of inverted
pyramid textured p-Si photocathodes covered conformally and continuously
with a thickness-gradient cobalt phosphide (Co2P) layer,
which not only effectively isolates p-Si from aqueous electrolyte
to avoid corrosion but also efficiently catalyzes the solar-driven
hydrogen evolution reaction (HER). Thanks to the unique inverted pyramid
structure, the drop-cast Co2P can distribute all over the
p-Si photocathode and form a macroscopically continuous but locally
nonuniform layer on the sidewalls of each inverted pyramid. The local
nonuniform distribution enables light absorption to be partially separated
from catalytic activity. Consequently, the as-fabricated Co2P-coated p-Si photocathode exhibits a high photocurrent density of
35.2 mA cm–2 at 0 V versus the reversible hydrogen
electrode under AM 1.5G illumination and can photoelectrochemically
catalyze the HER above 30 mA cm–2 at least 150 h
without notable degradation.
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cmsolar-driven hydrogen productionStable Solar Hydrogen Evolution Photocathode Silicondrop-cast Co 2 Pcatalyzephotocurrent densitynonuniformphotoelectrochemical water splittingsolar-driven hydrogen evolution reactionmAthickness-gradient cobalt phosphideHERAM 1.5 G illuminationas-fabricated Co 2 P-coated p-Si photocathode exhibitsCo 2 P