Zhengqing Liu

Colloidally synthesized MoSe2/graphene hybrid nanostructures as efficient electrocatalysts for hydrogen evolution

Uniform 3D MoSe2 layered nanostructures grown on graphene nanosheets to form high quality MoSe2/graphene hybrid nanostructures were synthesized by using a facile wet chemistry strategy. Owing to its unique structure, the as-harvested MoSe2/graphene hybrid exhibited excellent electrocatalytic activity in the hydrogen evolution reaction, i.e. it had a low onset overpotential of 125 mV, a small Tafel slope of 67 mV per decade and outstanding stability.

MoSe2 nanosheets grown on carbon cloth with superior electrochemical performance as flexible electrode for sodium ion batteries

A flexible MoSe2/CF composite has been synthesized by a simple solvothermal method. MoSe2 nanosheets with a thickness of 20 nm are grown uniformly on the surface of the carbon fibers. The MoSe2/CF can be used as a self-supporting anode directly with superior electrochemical performance for sodium ion batteries.

Assembled 3D electrocatalysts for efficient hydrogen evolution: WSe2 layers anchored on graphene sheets

A new 3D composite electrocatalytic material is produced by growing WSe2 thin layers vertically on 2D reduced graphene oxide nanosheets. The material has improved electrode/electrolyte interactions and efficient catalytic properties due to the rich defects, a 3D hybrid configuration, and the direct integration of WSe2 onto the graphene sheets, which can significantly prevent the aggregation of WSe2 and promote the conductivity of the material. As demonstrated, the as-harvested WSe2/graphene hybrid exhibits excellent electrocatalytic activity in the hydrogen evolution reaction (HER), such as a low onset overpotential of −100 mV, a small Tafel slope of 64 mV per decade and outstanding stability.

Monodisperse photoluminescent and highly biocompatible bioactive glass nanoparticles for controlled drug delivery and cell imaging

Bioactive glass nanoparticles (BGNs) have attracted widespread interest recently and been explored as the promising drug or gene delivery carriers due to their high biocompatibility and tissue repair ability. However, the synthesis of monodispersed photoluminescent BGNs and their corresponding biomedical applications are still not explored. Here, for the first time, we report monodispersed Eu-doped photoluminescent bioactive glass nanoparticles (BGN-Eu) and demonstrate their biomedical applications for drug delivery and cell imaging. By a long chain amine assisted sol-gel method, we synthesized the monodispersed BGN-Eu with combined dual functions of bioactivity and luminescence properties, and further investigated their physicochemical structure, biomineralization activity and biomedical applications. As-prepared BGN-Eu possessed the spherical morphology, relatively homogeneous particle size (200 ∼ 400 nm) and representative red fluorescence emission characteristic of Eu3+ at 616 nm. In simulated body fluids (SBFs), the BGN-Eu demonstrated excellent bioactivity by inducing biological apatite mineralization. BGN-Eu also presented controlled drug (theophylline) loading ability and release behavior. The osteoblast (MC3T3) growth was significantly enhanced when incubated with different dosages of BGN-Eu, suggesting the high biocompatibility. In addition, BGN-Eu was successfully used to label the MC3T3 cell by a strong red fluorescence with low background noise. Our results suggest the great potential of BGN-Eu as multifunctional bioactive nanomaterials for cell imaging and bone tissue regeneration applications.

High quality sulfur-doped titanium dioxide nanocatalysts with visible light photocatalytic activity from non-hydrolytic thermolysis synthesis

A facile non-hydrolytic thermolysis route for monodisperse sulfur doped TiO2 nanocatalysts is demonstrated. Compared with the as-obtained undoped TiO2 nanocatalysts, the sulfur doped TiO2 nanocatalysts present obvious enhanced visible light activation for the degradation of rhodamine B and methylene blue dyes under the artificial visible light (λ = 420–770 nm) irradiation.

Core–shell structured CeO2@MoS2 nanocomposites for high performance symmetric supercapacitors

MoS2 ultrathin nanosheet-coated CeO2 hollow sphere (CeO2@MoS2) nanocomposites with a 3D core–shell architecture were successfully prepared via a facile wet chemistry strategy. The core–shell structured CeO2@MoS2 nanocomposites were systematically characterized using XRD, SEM, TEM and XPS analysis techniques. As a proof of concept application, symmetric supercapacitors were assembled using the CeO2@MoS2 nanocomposites, and aqueous 1 M Na2SO4 or 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid as the electrolyte. The as-obtained CeO2@MoS2 nanocomposites exhibited superior performance in symmetric supercapacitors.

Room temperature stable COx-free H2 production from methanol with magnesium oxide nanophotocatalysts

A novel facile strategy was developed to synthesize MgO nanocrystals for producing H2 through photodecomposing methanol. Methanol, which contains 12.6 weight percent hydrogen, is a good hydrogen storage medium because it is a liquid at room temperature. However, by releasing the hydrogen, undesirable CO and/or CO2 byproducts are formed during catalytic fuel reforming. We show that alkaline earth metal oxides, in our case MgO nanocrystals, exhibit stable photocatalytic activity for CO/CO2-free H2 production from liquid methanol at room temperature. The performance of MgO nanocrystals toward methanol dehydrogenation increases with time and approaches ~320 μmol g−1 hour−1 after a 2-day photocatalytic reaction. The COx-free H2 production is attributed to methanol photodecomposition to formaldehyde, photocatalyzed by surface electronic states of unique monodispersed, porous MgO nanocrystals, which were synthesized with a novel facile colloidal chemical strategy. An oxygen plasma treatment allows for the removal of organic surfactants, producing MgO nanocrystals that are well dispersible in methanol.

Synthesis of High-Quality α-MnSe Nanostructures with Superior Lithium Storage Properties

High-quality α-MnSe nanocubes were successfully prepared for the first time by an effective hot injection synthesis strategy. This approach was simple but robust and had been applied to the controllable synthesis of different sizes and diverse morphologies of α-MnSe nanostructures. The crystal phases, compositions, and microstructures of these nanostructures had been systematically characterized with a series of techniques. As a proof-of-concept application, the as-prepared α-MnSe nanocubes were used as an anode material for a lithium ion battery, which exhibited superior rate ability and ultralong cycle stability in half-cell and full-cell tests. Importantly, the phase transition from α-MnSe to β-MnSe during the electrochemical process was proved by ex situ X-ray diffraction and selected area electron diffraction. The excellent electrochemical performance of α-MnSe endowed its potential as an anode material candidate for high performance lithium storage.

Phosphine-free, low-temperature synthesis of tetrapod-shaped CdS and its hybrid with Au nanoparticles.

Tetrapod-shaped CdS colloidal nanocrystals are synthesized using a facile, phosphine-free synthesis approach at low temperature. The arm length and diameter of CdS tetrapods can be easily tuned by using different source of sulphureous precursors, i.e., sulfur powder, thioacetamide, and sodium diethyldithiocarbamate. Moreover, the growth of Au nanoparticles onto CdS to form metal-semiconductor hybrid nanocrystals is also demonstrated. The tetrapod-shaped CdS nanocrystals exhibit strong arm-diameter-dependent absorption and photoluminescence characteristics. Importantly, the as-obtained CdS tetrapods exhibit promising photocatalytic activity for the water-splitting reaction in photoelectrochemical cells.

Constructing monodispersed MoSe2 anchored on graphene: a superior nanomaterial for sodium storage

We reported a facile and robust one-pot wet chemistry strategy to achieve the growth of uniform three dimensional (3D) MoSe2 ultrathin nanostructures on graphene nanosheets to form high quality MoSe2/rGO hybrid nanostructures. Owing to the graphene as a support, it can significantly prevent the aggregation of MoSe2 and the distribution of MoSe2 on graphene was highly uniform. Importantly, due to the unique structures, the as-harvested MoSe2/rGO hybrid exhibited excellent electrochemical performance as anode materials for sodium-ion battery (SIB). When evaluated in a half cell system, the MoSe2/rGO hybrid nanostructures could deliver a capacity of 200.2 mA h g−1 at 8 A g−1 and maintain a capacity of 230.1 mA h g−1 over 100 cycles at 5 A g−1. When coupled with Na3V2(PO4)3 cathode in a full cell system, the material could deliver a discharge capacity of 363.1 mA h g−1 at the current density of 0.5 A g−1. Moreover, a discharge capacity of 56.4 mA h g−1 could be achieved even at a high current density of 10 A g−1, which clearly suggested the high power capability of MoSe2/rGO hybrid nanostructures for sodium ion energy storage.摘要本文采用一种简单有效的湿化学策略将三维MoSe2超薄纳米结构均匀分散在石墨烯纳米片上, “一锅法”制备得到了MoSe2/rGO纳米复合结构. 石墨烯作为支撑, 不但能有效防止MoSe2的团聚, 而且使MoSe2均匀分散在石墨烯纳米片上. 由于这种独特的复合结构,MoSe2/rGO作为钠离子电池负极材料表现出优异的电化学性能. 在半电池中, MoSe2/rGO复合纳米材料在8 A g−1电流密度下提供的容量为200.2 mA hg−1, 在5 A g−1电流密度下循环100次, 其容量可保持在230.1 mA h g−1. 当和Na3V2(PO4)3正极组成钠离子全电池, 在0.5 A g−1的电流密度下提供的容量为200.2 mA h g−1, 即使在10 A g−1的高电流密度下, MoSe2/rGO复合纳米材料仍然可以获得56.4 mA h g−1放电容量, 表明MoSe2/rGO纳米复合材料作为钠离子存储材料具有较高的功率密度.