Water electrolysis at high current density (1000 mA cm−2 level) with excellent durability especially in neutral electrolyte is the pivotal issue for green hydrogen from experiment to industrialization. In addition to the high intrinsic activity determined by the electronic structure, electrocatalysts are also required to be capable of fast mass transfer (electrolyte recharge and bubble overflow) and high mechanical stability. Herein, the 2D CoOOH sheet-encapsulated Ni2P into tubular arrays electrocatalytic system was proposed and realized 1000 mA cm−2-level-current-density hydrogen evolution over 100 h in neutral water. In designed catalysts, 2D stack structure as an adaptive material can buffer the shock of electrolyte convection, hydrogen bubble rupture, and evolution through the release of stress, which insure the long cycle stability. Meanwhile, the rich porosity between stacked units contributed the good infiltration of electrolyte and slippage of hydrogen bubbles, guaranteeing electrolyte fast recharge and bubble evolution at the high-current catalysis. Beyond that, the electron structure modulation induced by interfacial charge transfer is also beneficial to enhance the intrinsic activity. Profoundly, the multiscale coordinated regulation will provide a guide to design high-efficiency industrial electrocatalysts.
To obtain a pure product without the isomer byproducts
is a goal
that many chemists are pursuing. As one kind of very important synthesis
method, the photochemical reaction is simple and straightforward yet
low-selective. In this work, a coordination interaction-based oriented
synthesis strategy has been proposed to realize the precise stereochemical
control of the isomeric cyclic compounds in the photocycloaddition
reaction. Through fixing the reactants via coordination interactions,
the arrangements and configurations of the reactants can be adjusted,
thereby successfully producing all of the related photocycloaddition
products without isomer byproducts for the first time. This work not
only provides a new route to synthesize the pure cyclic compounds
but also expands the application of the photocycloaddition reaction.
Regioselective photodimerization of trans-4-styrylpyridine (4-spy) derivatives is performed using pseudorotaxane-like Zn-based metal organic frameworks MOFs as templates. The formation of rctt-HT (head-to-tail) dimers is achieved by confining pairs of coordinated 4-spy derivative ligands within hexagonal windows and then irradiating them with UV light. It is also possible to achieve a photodimerization reaction where two different substituted 4-spy ligands are included in such a MOF material. The ether bond formation is employed to protect the sensitive -OH group of HO-spy and the methyl group of CH O-spy is subsequently removed after the formation of cyclobutane derivative in the CH O-spy-based MOF. Introducing substituents at the 2- or 3-position of the phenyl group of 4-spy does not significantly affect the rate of the dimerization process except in the case of the strongly electron-withdrawing nitro group where the rate is significantly decreased. These results are in striking contrast to the mixtures of photoproducts and low yields obtained by untemplated photodimerization in organic solvents.
Herein, a novel signaling mechanism for constructing fluorescent probes was demonstrated for the first time based on modulation of the unique rotation of the N-N single bond in the acetohydrazide group. According to the new signaling mechanism, a fluorescent probe for hypochlorite was then judiciously developed.
A single-layer of 2D metal–organic framework nanosheet was elaborately prepared by a facile exfoliation approach and showed unprecedented performance in removing congo red.
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