The first example of a polystyrene bearing two distinct reagent groups has been prepared. This phosphine and amine functionalized material was used in one-pot Wittig reactions with an aldehyde and either an α-halo-ester, -ketone, or -amide. Due to the heterogeneous nature of the polymer, the desired alkene product of these reactions could be isolated in excellent yield in essentially pure form after only filtration and solvent removal.
As the demand of fossil fuels continues to expand, hydrogen energy is considered a promising alternative energy. In this work, the NiTiO 3 −CuI-GD ternary system was successfully constructed based on morphology modulation and energy band structure design. First, the one-pot method was used to cleverly embed the cubes CuI in the stacked graphdiyne (GD) to prepare the hybrid CuI-GD, and CuI-GD was anchored on the surface of NiTiO 3 by simple physical stirring. The unique spatial arrangement of the composite catalyst was utilized to improve the hydrogen production activity under light. Second, to combine various characterization tools and energy band structures, we proposed an step-scheme (S-scheme) heterojunction photocatalytic reaction mechanism, among them, the tubular NiTiO 3 formed by the selfassembled of nanoparticles provided sufficient sites for the anchoring of CuI-GD, and the thin layer GD acted as an electron acceptor to capture a large number of electrons with the help of the conjugated carbon network; cubes CuI could consume holes in the reaction system; the loading of CuI-GD greatly improved the oxidation and reduction ability of the whole catalytic system. The S-scheme heterojunction accelerated the transfer of carriers and improved the separation efficiency. The experiment provides a new insight into the construction of an efficient and eco-friendly multicatalytic system.
It
is still a great challenge to develop photocatalysts with high
efficiency and low cost to reach the scale of industrialization. In
this work, we prepared an S-type heterojunction photocatalyst with
Co3S4 nanoparticles supported on g-C3N4/α-Fe2O3. Characterizations,
such as PL, UV–vis, electrochemical impedance spectroscopy,
and linear sweep voltammetry, proved that the composite material had
excellent photoelectrochemical performance and good stability. The
hydrogen evolution amount of g-C3N4/α-Fe2O3/Co3S4 is as high as 191.41
μmol, which is about 30 times that of pure Co3S4 (6.38 μmol). The improvement performance of a composite
material could be attributed to the following points: the EY molecules
not only increase the light absorption rate of the samples but also
act as electron donors; the highly dispersed Co3S4 nanoparticles provide a large number of reduction sites; and the
constructed S-scheme heterojunction consumes useless electrons and
holes in the hydrogen production system and utilizes the strong redox
potential of the composite material to promote the separation of photogenerated
carriers. In particular, Co3S4 nanoparticles
with different degrees of dispersion were prepared by changing the
preparation sequence of the composite catalyst. The design ideas of
this experiment can provide an effective reference for the synthesis
of efficient and stable multiple photocatalyst systems.
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