posted on 2020-03-09, 19:13authored byLei Zhu, Yi Liu, Xingcui Peng, Yibao Li, Yu-Long Men, Peng Liu, Yun-Xiang Pan
Graphene
oxide (GO) nanosheets are promising noble-metal-free catalysts. However,
the catalytic activity and selectivity of GO are still very low. Herein,
GO is first functionalized via noncovalent interactions by an aspartic
acid modified anhydride having COOH groups to form A-GO. A-GO is more
conductive and hydrophilic than GO and P-GO synthesized via functionalizing
GO by a COOH-free anhydride. Then, we load CdS nanoparticles, which
are responsible for absorbing light to produce charge carriers, on
A-GO to fabricate a CdS/A-GO photocatalyst without noble metals for
the photoreduction of CO2 by H2O. CdS/A-GO exhibits
a higher photoreduction efficiency than that of CdS/GO and CdS/P-GO.
The main carbon-based photoreduction product of CdS/A-GO is CH3OH, whereas that of CdS/GO and CdS/P-GO is CO. The more conductive
and hydrophilic A-GO triggers a more efficient electron transfer,
CO2 adsorption, and production of hydrogen atoms from H2O dissociation, thus leading to the higher photoreduction
efficiency and product change on CdS/A-GO. Besides, the COOH groups
of the aspartic acid modified anhydride supply their hydrogen atoms
to promote the conversion from CO2 to CH3OH
on CdS/A-GO. Therefore, noncovalently functionalizing GO with different
active species can efficiently improve the catalytic performance of
GO. This opens a new way to design and construct noble-metal-free
catalysts with enhanced activity and selectivity.