am6b00028_si_001.pdf (770.89 kB)
Rapid Construction of ZnO@ZIF‑8 Heterostructures with Size-Selective Photocatalysis Properties
journal contribution
posted on 2016-03-21, 00:00 authored by Xianbiao Wang, Jin Liu, Sookwan Leong, Xiaocheng Lin, Jing Wei, Biao Kong, Yongfei Xu, Ze-Xian Low, Jianfeng Yao, Huanting WangTo selectively remove heavy metal
from dye solution, inspired by
the unique pore structure of ZIF-8, we developed a synthetic strategy
for rapid construction of ZnO@ZIF-8 heterostructure photocatalyst
for selective reduction of Cr(VI) between Cr(VI) and methylene blue
(MB). In particular, ZnO@ZIF-8 core–shell heterostructures
were prepared by in situ ZIF-8 crystal growth using ZnO colloidal
spheres as template and zinc source within 8–60 min. The shell
of the resulting ZnO@ZIF-8 core–shell heterostructure with
a uniform thickness of around 30 nm is composed of ZIF-8 crystal polyhedrons.
The concentration of organic ligand 2-methylimidazole (Hmim) was found
to be crucial for the formation of ZnO@ZIF-8 core–shell heterostructures.
Different structures, ZnO@ZIF-8 core–shell spheres and separate
ZIF-8 polyhedrons could be formed by altering Hmim concentration,
which significantly influences the balance between rate of Zn2+ release from ZnO and coordinate rate. Importantly, such
ZnO@ZIF-8 core–shell heterostructures exhibit size-selective
photocatalysis properties due to selective adsorption and permeation
effect of ZIF-8 shell. The as-synthesized ZnO@ZIF-8 heterostructures
exhibited enhanced selective reduction of Cr(VI) between Cr(VI) and
MB, which may find application in the dye industry. This work not
only provides a general route for rapid fabrication of such core–shell
heterostructures but also illustrates a strategy for selectively enhanced
photocatalysis performance by utilizing adsorption and size selectivity
of ZIF-8 shell.