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An on-demand solar hydrogen-evolution system for unassisted high-efficiency pure-water splitting
Solar water splitting of pure water offers an attractive means for sustainable and carbon-free H 2 production. However, current photocatalytic H 2 production systems still suffer from two basic issues: the kinetic bottleneck for O 2 release and the easy toxicity of the photocatalysts. Here, we devel...
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Published in: | Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2019, Vol.7 (29), p.17315-17323 |
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Main Authors: | , , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Solar water splitting of pure water offers an attractive means for sustainable and carbon-free H
2
production. However, current photocatalytic H
2
production systems still suffer from two basic issues: the kinetic bottleneck for O
2
release and the easy toxicity of the photocatalysts. Here, we developed a consolidated photocatalyst, namely g-C
3
N
3.5
(O
0.5
H
0.5
), that can boost sustainable and superior H
2
evolution without using any sacrificial reagent. By conceptual design analysis as the guideline for three synthetic steps, the surface hydroxylation structure of g-C
3
N
3.5
(O
0.5
H
0.5
) concurrently increases the toxicity resistance and maximizes the charge separation for H
2
evolution. The obtained surface-hydroxylated g-C
3
N
3.5
(O
0.5
H
0.5
) photocatalyst exhibited unassisted high-efficiency pure-water-splitting activity, with a benchmark H
2
-evolution rate up to 947.7 μmol h
−1
g
−1
under visible-light irradiation. Notably, the quantum efficiency of the g-C
3
N
3.5
(O
0.5
H
0.5
) suspension reached ∼10.6 and ∼2.5% at 420 and 520 nm, respectively, 10-20 times that of pristine g-C
3
N
4
. For the first time, we observed a key phenomenon that H
2
O molecules can rapidly capture the photoexcited holes to produce H
2
O
2
, which can greatly promote the efficient charge separation for high H
2
evolution.
A surface hydroxylation structure of g-C
3
N
3.5
(O
0.5
H
0.5
) photocatalyst was designed to concurrently increase the toxicity resistance and maximize the charge separation for H
2
evolution. |
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ISSN: | 2050-7488 2050-7496 |
DOI: | 10.1039/c9ta05142b |