Xiao-Jun Lv

P25-Graphene Composite as a High Performance Photocatalyst

Herein we obtained a chemically bonded TiO(2) (P25)-graphene nanocomposite photocatalyst with graphene oxide and P25, using a facile one-step hydrothermal method. During the hydrothermal reaction, both of the reduction of graphene oxide and loading of P25 were achieved. The as-prepared P25-graphene photocatalyst possessed great adsorptivity of dyes, extended light absorption range, and efficient charge separation properties simultaneously, which was rarely reported in other TiO(2)-carbon photocatalysts. Hence, in the photodegradation of methylene blue, a significant enhancement in the reaction rate was observed with P25-graphene, compared to the bare P25 and P25-CNTs with the same carbon content. Overall, this work could provide new insights into the fabrication of a TiO(2)-carbon composite as high performance photocatalysts and facilitate their application in the environmental protection issues.

Hydrogen evolution from water using semiconductor nanoparticle/graphene composite photocatalysts without noble metals

Semiconductor nanoparticle/graphene composite photocatalysts containing semiconductor CdS or TiO2 nanoparticles are fabricated by one-pot solution methods and their structures are characterized. The photocatalytic hydrogen-generating capabilities of the composite photocatalysts are investigated in the presence of sacrificial reagent and compared with those of the same semiconductor materials with platinum as a co-catalyst under the same conditions. The results obtained by the measurements of time-resolved emission spectra, photocurrent generated response and electrochemical impedance spectra revealed that graphene attached to semiconductor surfaces can efficiently accept and transport electrons from the excited semiconductor, suppressing charge recombination and improving interfacial charge transfer processes. The semiconductor nanoparticle/graphene photocatalysts displayed higher activity for photocatalytic hydrogen evolution, which can be compared with the hydrogen-generating efficiency of systems containing the well-known Pt co-catalyst. This work provides an inexpensive means of harnessing solar energy to achieve highly efficient hydrogen evolution without noble metals.

Synergetic effect of Cu and graphene as cocatalyst on TiO2 for enhanced photocatalytic hydrogen evolution from solar water splitting

In photocatalytic solar water splitting systems, non-noble and highly active cocatalysts have always been pursued with tremendous interest. Herein an active and cheap photocatalyst, using Cu and graphene synergetically as co-catalysts immobilized on TiO2, was studied. This synergetic photocatalyst displayed enhanced photocatalytic hydrogen generation from water splitting in the presence of methanol as a sacrificial reagent. The hydrogen generation efficiency from the Cu–graphene synergetic cocatalyst was about 5 times higher than that of a pure graphene cocatalyst, and can be compared with that of systems containing the well-known Pt cocatalyst. Therefore this Cu–graphene synergetic cocatalyst provides an inexpensive means of harnessing solar energy to achieve efficient hydrogen evolution from water splitting.

Large Stokes shift induced by intramolcular charge transfer in N,O-chelated naphthyridine-BF2 complexes.

Novel N,O-chelated naphthyridine-BF(2) complexes with push-pull structures have been synthesized and characterized. Spectral investigations on these complexes reveal that photoinduced intramolecular charge transfer occurs and results in a large Stokes shift, which is further supported by density functional theory based theoretical calculations.

Cobalt phosphide as a highly active non-precious metal cocatalyst for photocatalytic hydrogen production under visible light irradiation

Cobalt phosphide (Co2P) is found, for the first time, to be a novel cocatalyst for efficient photocatalytic hydrogen evolution for a system containing CdS nanorods as a photocatalyst and DL-mandelic acid as an electron donor in water. Under optimal conditions, the H2-production rate can reach up to 19 373 μmolh−1 g−1 after 10 h of LED light irradiation. Meanwhile, DL-mandelic acid can be oxidized to benzoylformic acid by the photo-generated holes of CdS nanorods, providing a green and economic way to synthesize benzoylformic acid from DL-mandelic acid.

N-doped TiO2 nanotubes/N-doped graphene nanosheets composites as high performance anode materials in lithium-ion battery

To improve the electrochemical performance of TiO2 nanotube as anode materials in Li-ion batteries, N-doped TiO2 nanotube/N-doped graphene composites were prepared via hydrothermal synthesis followed by heat treatment in the presence of urea. The N-doped TiO2 nanotubes/N-doped graphene composites were characterized by X-ray powder diffraction, transition electron microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical experiments demonstrated that the as-prepared sample exhibit superior discharge capacity (up to 369 mA h g−1 at 0.1 A g−1) as well as excellent rate ability (90 mA h g−1 even at 5 A g−1 at 180th cycle) as anode materials in lithium-ion batteries.

Photocatalytic reduction of CO2 with H2O over a graphene-modified NiOx–Ta2O5 composite photocatalyst: coupling yields of methanol and hydrogen

A reduced graphene modified Ta2O5 photocatalyst (Ta2O5–rG) was prepared using a one-step hydrothermal method, and the photocatalytic reduction of an aqueous CO2 solution to CH3OH and H2 using the NiOx–Ta2O5–rG photocatalyst was performed. Due to graphenes electron transfer and collecting characteristics, reduced graphene was found to be important in achieving high methanol yields for this multi-electron reduction process. The NiOx–Ta2O5–rG photocatalyst also showed good production selectivity for the competing reactions of CH3OH and H2 generation in aqueous CO2 or CO2/NaHCO3 solution.

Aggregation‐Induced Photoluminescent Changes of Naphthyridine–BF2 Complexes

Luminous boron: new 1,8-naphthyridine-BF(2) complexes with strong emissions both in solution and in the solid state have been developed. Aggregation-induced blueshifts of emissions in DMSO/water mixtures and solvent-influenced luminescence in crystalline states have been observed and are discussed.

Electrochemical Water Oxidation by In Situ-Generated Copper Oxide Film from [Cu(TEOA)(H2O)2][SO4] Complex

Although many noble-metal oxide catalysts show high activities and low overpotentials for water oxidation, there remain challenges in the sustainable developments of more inexpensive, efficient, and robust catalysts. Here, we report a heterogeneous copper oxide film toward water oxidation formed upon the oxidative polarization of an acetate electrolyte containing Earth-abundant Cu(II) salts in combination with commercially available triethanolamine (TEOA) as the catalyst precursor. A 1:1 molar ratio of TEOA coordinates to Cu(II) is favored in aqueous solution and the single crystal of the complex was obtained. The film has a modest overpotential of 550 mV and the catalytic performance of the material is demonstrated by long-term electrolysis at 1.3 V vs normal hydrogen electrode, a stable current density persists for at least 3 h, and a Faradaic efficiency of almost 100% is obtained.

Highly efficient electrocatalytic hydrogen production by nickel promoted molybdenum sulfide microspheres catalysts

Ni-promoted MoS2 microspheres consisting of nanosheets have been prepared via a facile one-pot hydrothermal synthesis for the first time. The electrochemical hydrogen evolution reaction (HER) results demonstrated that the Ni-promoted MoS2 catalysts showed superior catalytic activity in the HER compared to pure MoS2 catalysts.