In this work, small sizes of hydrophobic copper sulfide nanoparticles (CuS NPs, ∼3.8 nm in diameter) have been successfully prepared from the reaction of copper chloride with sodium diethyldithiocarbamate (SDEDTC) inside a heated oleylamine solution. These CuS NPs displayed strong absorption in the 700-1100 nm near-infrared (NIR) region. By coating CuS NPs with DSPE-PEG2000 on the surface, the as-synthesized CuS@DSPE-PEG NPs exhibited good water solubility, significant stability and biocompatibility, as well as excellent photothermal conversion effects upon exposure to an 808 nm laser. After intravenous administration to mice, the CuS@DSPE-PEG NPs were found to passively target to the tumor site, and tumor tissues could be ablated efficiency under laser irradiation. In addition, CuS@DSPE-PEG NPs do not show significant toxicity by histological and blood chemistry analysis, and can be effectively excreted via metabolism. Our results indicated that CuS@DSPE-PEG NPs can act as an ideal photothermal agent for cancer photothermal therapy.
A combined technique
of production and storage of ammonia (NH
3
) from electroreduction
of nitrate (NO
3
–
) through one material
is highly desirable but remains a huge challenge.
Herein, we proposed a proof-of-concept strategy for combined NH
3
production and storage from electroreduction of NO
3
–
through elaborately designing a single-site Cu
II
-bipyridine-based thorium metal–organic framework
(Cu@Th-BPYDC). Noticeably, the single Cu
II
site, anchored
by a solid–liquid postsynthetic metalation within Th-BPYDC,
shows a novel square coordination structure, as determined by the
single-crystal X-ray diffraction. This strongly implies its enormous
potential as an open metal site and consequently enables excellent
performance in electroreduction of NO
3
–
for NH
3
production, giving 92.5% Faradaic efficiency
and 225.3 μmol h
–1
cm
–2
yield.
Impressively, we can further use Cu@Th-BPYDC material to effectively
capture the previously produced NH
3
from electroreduction
of NO
3
–
, affording an uptake up to 20.55
mmol g
–1
at 298 K at 1 bar. The results in this
work will outline a new direction toward the combined technique for
advanced electrocatalysis such as gas production
plus
storage/or separation.
Constructing metal−organic framework (MOF) electrocatalysts toward an acidic oxygen evolution reaction (OER) remains a huge challenge owing to the generally poor stability of MOFs during the acidic OER process. Herein, Th-MOF-supported semirigid single-metal-site catalysts of MCl 2 @Th-BPYDC (M = Cu, Co, Ni) were prepared by postmetalation of a bipyridyl Th-MOF (Th-BPYDC) crystal toward an acidic OER. Impressively, the structure of the anchoring single-metal site can be well resolved by single-crystal X-ray diffraction, giving a nearsquare-planar MN 2 Cl 2 coordination geometry, indicative of its potential as a double-accessible open-metal site and an unusual semirigid character because of two rotatable charge-balance Cl − anions. The optimal CoCl 2 @Th-BPYDC not only discloses an outstanding acidic OER activity comparable to commercial IrO 2 but also exhibits a high electrocatalytic stability, which is attributed to the combination of the robust rigid Th-BPYDC framework, the strong chelating coordination between single-metal-site with bipyridine N in BPYDC ligand, and an accessible open single-metal site. More importantly, as unveiled by theoretical calculations and kinetic analysis, the single-metal-site catalysts show an unusual semirigid character during the OER process, totally different from the well-known MN 4 rigid single-site catalysts since Cl atoms are found to rotate freely to provide suitable geometric space when attaching and activating reaction intermediates, thus largely reducing the reaction energy barrier.
A research-style laboratory experiment
composed of the synthesis
of MOF-74 materials, related structural characterization, and the
cutting-edge application of electrocatalytic oxygen evolution reaction
(OER) has been designed toward advanced undergraduates at East China
University of Technology (ECUT). The desired monometallic MOF-74 (Ni-MOF-74
and Co-MOF-74) and bimetallic NiCo-MOF-74 were synthesized by students
using cheap raw materials under mild reaction conditions. Students
operated the modern instruments to perform powder X-ray diffraction
(PXRD), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric
analysis (TGA) applied extensively in chemical research to explore
whether the materials were successfully synthesized and the thermal
stability under the guidance of the instructor. The electrocatalytic
OER activity of bimetallic NiCo-MOF-74 was compared with monometallic
Ni-MOF-74 and Co-MOF-74 to explore and understand the bimetallic synergy
effect in MOFs materials. This experiment not only enabled students
to master the solvothermal method for MOFs synthesis but also provided
students the chance to operate several common chemical instruments
and master their functions, realizing the application of theoretical
knowledge to practice. Most importantly, this experiment helped students
realize the importance of MOFs in the electrochemical energy fields
and established a sense of teamwork by analyzing and discussing the
bimetallic synergy effect in NiCo-MOF-74 for OER catalysis.
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