posted on 2021-12-10, 19:36authored byChenjie Wang, Juan Xie, Ning Chen, Weifeng Chen, Penghui Bai, Hu Wang
Developing
high-efficiency, stable, and low-cost catalysts is essential
for water splitting to generate hydrogen. Herein, an abundant material,
g-C3N4 nanosheet, modified with a moderate amount
of Cu atoms to form a special Cu-N3 structure exhibits
excellent performance of photocatalytic hydrogen generation under
visible light illumination. The structure of Cu-N3 is formed
through Cu-atom-substituted C atoms in g-C3N4. X-ray absorption fine structure spectroscopy (XAFS) was employed
to confirm the Cu coordination and the special structure of Cu-N3. Doping of Cu atoms not only regulates the energy band structure
but also enhances the visible light absorption of g-C3N4 as confirmed by the UV–vis diffuse reflectance spectroscopy
and Mott–Schottky test, and significantly improves the separation
and transfer of photogenerated charges confirmed by the electrochemical
test. Therefore, the catalyst exhibits a superior photocatalytic hydrogen
production rate of 3774.35 μmol·g–1·h–1 and an apparent quantum efficiency (AQE) of 1.34%
under visible light illumination (at 427 nm), which are both more
than 3 times those of pure g-C3N4 nanosheets
(1116.07 μmol·g–1·h–1 and 0.40%, respectively).