Sulfonated hollow microporous organic polymers (S-HMOP) were prepared by template synthesis and post synthetic approach. The S-HMOP showed excellent non-covalent fixation ability towards various cationic dyes through ionic interaction. Among various dye systems, Zn-porphyrin loaded S-HMOP showed promising activity and stability in the decomposition of 4-chlorophenol under visible light irradiation.
CuO nanocubes were used for the synthesis of hollow and microporous Fe porphyrin networks (H-MFePN). In this synthesis, CuO nanocubes performed not only as networking catalysts but also as shape controlling templates. MFePN were formed on the surface of the CuO nanocubes through azide-alkyne cycloaddition of tetrakis(4-ethynylphenyl) Fe-porphyrin with 1,4-diazidobenzene. H-MFePN showed excellent catalytic activities in carbene insertion into N-H bonds, maintaining their activities during five recycle tests.
This work reports
the thinnest and smallest hollow N-doped carbon
boxes among recently reported hollow N-doped carbon materials. Hollow
and N-rich microporous organic networks (H-NMONs) were prepared by
the azide–alkyne Huisgen cycloaddition of tetra(4-ethynylphenyl)methane
and 1,4-diazidobenzene on the surface of Cu2O nanocubes
and the successive acid etching of inner Cu2O. The Cu2O nanocubes played roles of templates and networking catalysts.
The networking reaction generated N-rich triazole rings in the MON.
Heat treatment of H-NMONs under argon resulted in the formation of
hollow N-doped carbon boxes (H-NCBs). The diameter and shell thickness
of H-NCBs were 130 and 12 nm, respectively. The H-NCBs showed superior
electrochemical performance in H2SO4 electrolyte
as energy storage materials for supercapacitors, compared with that
in KOH electrolyte. Among the H-NCBs, H-NCB-900 which was obtained
by the heat treatment of H-NMON at 900 °C showed the best performance
with capacitances of 286 and 251 F/g at current densities of 1 and
10 A/g in two electrode coin cell type supercapacitors and maintained
the capacitances of 228 and 206 F/g at higher current densities of
50 and 100 A/g. Moreover, the H-NCB-900 showed excellent cycling stabilities
with ∼95% retention of the first capacitance after 10 000
cycles. The excellent electrochemical performance of H-NCBs can be
attributed to their efficient N-doping, hollow structure, and thin
thickness of shells.
We prepared a series of hollow sulfur-doped carbons with diverse S contents through the carbonization of microporous organic networks (MONs), which were synthesized through the Sonogashira coupling of thiophene moieties with different numbers of S atoms as building blocks. This preparation method enabled the doping level to be controlled without inducing any notable differences in textural and morphological characteristics, and these S-doped carbons did not show any notable differences in the chemical properties of carbon, regardless of the sulfur content. We used these well-controlled MON-derived carbons as a model to elucidate the role of sulfur dopants in the oxygen reduction reaction (ORR) and to investigate the relationship between the activities and work functions of carbonaceous catalysts. By excluding the effect of electrical properties of the S-doped carbon catalysts using conducting agents, we could successfully verify that increasing the number of dopants led to an enhancement in the ORR activities, and the high applicability of work function as the activity descriptor was also demonstrated. We believe that our experimental observations will provide a deeper understanding of carbonaceous electrocatalysts with p-block dopants, and the investigations performed in this study are also anticipated to serve as a rational guideline in designing carbonaceous catalysts for various electrochemical reactions.
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