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Crystalline tetragonal quasi-rounded AgGaS2 nanoplates with a diameter of about 40 nm were successfully synthetized by a facile one-pot hydrothermal process. The as-prepared product was characterized with X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption–desorption isotherms and UV–vis spectroscopy. Meanwhile, photocatalytic H2 evolution from water over the as-prepared AgGaS2 nanoplates loaded with CuS was explored using Na2S and Na2SO3 as sacrificial reagents. The results indicate that the AgGaS2 nanoplates loaded with CuS is an efficient photocatalyst under visible irradiation. More importantly, the photocatalytic H2 evolution is very rapid in the presence of the AgGaS2 nanoplates with CuS. In the first hour of irradiation, more than 65% of the total hydrogen production can be obtained and the rate is up to 772 μmol h−1 g−1. Furthermore, for practical purposes, the photocatalytic H2 evolution was studied as a function of content of loaded CuS, hydrothermal reaction temperature, hydrothermal reaction time, dosage of photocatalyst, and concentration of sacrificial reagents, respectively. At last, the formation mechanism of AgGaS2 nanoplates and the photocatalytic mechanism were preliminarily discussed.

Cu and Ni co-modified TiO2 nanoparticles (P25) were prepared by a simple hydrothermal process. Meanwhile, photocatalytic H2 evolution from water over the as-prepared Cu and Ni co-modified TiO2 nanoparticles was explored using methanol as a sacrificial reagent. The results indicate that the Cu and Ni co-modified TiO2 nanoparticles is an efficient and stable photocatalyst for photocatalytic hydrogen evolution from methanol aqueous solution. During the first 5-h irradiation, the rate is up to 13.5 mmol h−1 g−1. Moreover, the photocatalytic activity of the Cu and Ni co-modified TiO2 nanoparticles can remain almost unchanged after two successive cycles. And the hydrogen evolution rate is still up to 4.62 mmol h−1 g−1 in the eighth cycle. Therein, Cu–Ni bimetallic deposit serves as charge transferring sites and/or active sites, and plays an important role in the photocatalytic hydrogen evolution. The dramatic photocatalytic activity of the Cu and Ni co-modified TiO2 nanoparticles may be ascribed to the synergy effect between Cu and Ni. At last, the photocatalytic hydrogen evolution was studied as a function of content of Cu–Ni bimetallic deposit, molar ratio of Cu to Ni, hydrothermal reaction temperature, hydrothermal reaction time, pH, dosage of photocatalyst and concentration of sacrificial reagent, respectively.

In this work, the properties of dopamine and dopamine-quinone on gold nanoparticles (Au NPs) surface were studied by the constructed Au NPs/dopamine sensing platform using surface enhanced Raman scattering (SERS) spectroscopy. Interestingly, the Au NPs/dopamine-quinone exhibited the characteristic Raman band at 1270, 1335 and 1480 cm−1 at pH 10.0, whereas, no obvious Raman band of Au NPs/dopamine was observed at pH = 6.0. Also, dopamine-quinone could be reduced by glutathione (GSH) and dopamine could be oxidized easily by superoxide radical anion (O2 −), thus, this sensing platform could be used to determine the concentration of GSH and O2 − in a wide range. Importantly, the utility of Au NPs/dopamine platform was demonstrated in living HeLa and normal human liver (HL-7702) cells, and responded to the concentration changes of reactive oxygen species (ROS) in real time.

Wurtzite CuGaS2 was successfully synthesized in a facile one-pot hydrothermal process using CuCl, Ga(NO3)3 and thioacetamide as reagents. The as-prepared product was characterized with X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and UV–vis spectroscopy. Furthermore, the application of CuGaS2 obtained in the trace detection of l -noradrenaline was explored as a photoluminescent probe. The results indicate that the as-prepared sample is an aggregation of wurtzite CuGaS2 nanosheets and nanorods, and possess high crystallinity. This CuGaS2 hierarchical nanostructure can exhibit a strong emission at 832 nm with full width at half maximum of approximate 20 nm. In addition, the as-prepared CuGaS2 possess high sensitivity to l -noradrenaline in water with a detectable concentration of 5.0 × 10−7 mol L−1 when it used as a photoluminescent probe, implying that it is a promising candidate in the field of biological and chemical sensing in future.

A novel silanized metalloporphyrin cobalt monomer (SMPCM) was prepared by using 5,10,15,20-tetra(4-hydroxyphenyl)porphyrin cobalt (CoTHPP) and γ-isocyanatopropyltriethoxysilane (ICPTES) as the reactants. Followed by the hydrolysis–polymerization of the organosilanes in the axial direction and peripheries of the SMPCM, the ordered porphyrin thin films with uniform morphology were facilely prepared on various substrates by the self-directed assembly of the SMPCM. The thin films formed was characterized by UV-vis spectra, electron microscopies, X-ray diffraction spectra, Fourier transform infrared spectra, fluorescence spectra and X-ray photoelectron spectra. The results demonstrated that the axial assembly between the Co3+ ion in the center of porphyrin macrocycle and ICPTES can prevent porphyrin lamellar from curling in horizontal direction, and then enhanced the order and stability of the films. Especially, the thin films possessed high, sensitive and stable photoelectronic response.

Herein, a series of novel SrTiO3 (STO) based photocatalysts loaded with Cu–Pt bimetallic co-catalysts have been synthesized through a simple photodeposition process. This photocatalyst of STO/Cu–Pt displayed enhanced photocatalytic activity for hydrogen generation from water in the presence of methanol as a sacrificial reagent. Moreover, the hydrogen generation efficiency over the STO/Cu95–Pt5 photocatalyst was about 2.79 and 1.76 times of STO/Cu100–Pt0 and STO/Cu0–Pt100, respectively. Thus, this Cu–Pt synergetic cocatalyst presents an inexpensive and high efficiency cocatalyst to achieve efficient hydrogen evolution from water.

In the present work, a photoelectrochemical system containing eosin Y, rhodamine B and graphene loaded with Pt nanoparticles was fabricated. The synergistic effect between eosin Y and rhodamine B was explored using photoelectrochemical techniques. The results show that there exists an obvious synergistic effect between eosin Y and rhodamine B in the as-fabricated photoelectrochemical system. Compared with the photoelectrochemical systems containing only eosin Y or rhodamine B, the photoelectrochemical system containing eosin Y and rhodamine B exhibits higher photoelectrochemical response. When graphene loaded with Pt nanoparticles is cosensitized by eosin Y and rhodamine B, the photocurrent is about 71% higher than the sum of the photocurrents of the photoelectrochemical system containing eosin Y and the photoelectrochemical system containing rhodamine B. This synergistic effect may be ascribed to the energy transfer from eosin Y to rhodamine B under irradiation. Herein, the Pt nanoparticles play an important role in the photovoltaic performance. The synergistic effect between eosin Y and rhodamine B cannot be observed if the Pt nanoparticles are absent. Moreover, the synergistic effect was investigated as a function of pH, content of Pt, molar ratio of eosin Y to rhodamine B, and total concentration of eosin Y and rhodamine B, respectively.

In the present work, TiO2 nanotube arrays were fabricated on metallic Ti meshes using anodic oxidation method, and decorated with Pt via electrodeposition. Meanwhile, the application of the TiO2 nanotube arrays loaded with Pt in a continuous flow system was explored as a photocatalyst for H2 evolution from water. Furthermore, for practical purposes, the photocatalytic H2 evolution was studied as a function of content of loaded Pt, annealing temperature, anodic oxidation time, and flow velocity. The results indicate that the TiO2 nanotube arrays fabricated on metallic Ti meshes are an efficient photocatalyst which can be used in a continuous flow system for H2 evolution from water. During the first hour of irradiation, a rate of H2 evolution of approximately 4.6 L m−2 h−1 was achieved under optimal conditions. Moreover, the photocatalytic activity of the TiO2 nanotube arrays fabricated on Ti meshes is obviously higher than that of the TiO2 nanotube arrays fabricated on metallic Ti foils. The rate of H2 evolution can increase by a factor of 5 when the TiO2 nanotube arrays are fabricated on metallic Ti meshes. Finally, the photocatalytic mechanism was preliminarily discussed.

By a layer-by-layer self-assembly method, reduced graphene oxide (RGO)-based composite films with high photoelectronic activity were assembled with 5,10,15,20-tetrakis(p-N,N,N-trimethylanilinium)porphyrin tetraiodide (TAPPI) and copper sulfophthalocyanine (CuTsPc) as the co-sensitizers. The π–π interaction and electrostatic interaction were the main driving forces of the assembly. The linear dependence of the absorption on the layer numbers of the films demonstrated the formation of the ordered films. In the composite film, an efficient photoinduced electron transfer can take place as evidenced by fluorescence spectra. Furthermore, the photoelectronic response for the RGO/TAPPI/CuTsPc film was higher than that of the RGO/TAPPI film, the RGO/CuTsPc film or the TAPPI/CuTsPc film. The complementary absorption spectra of TAPPI and CuTsPc and the quick transfer of photoproduced electrons could be the main reasons for the enhanced photoelectronic response in the RGO/TAPPI/CuTsPc film.

The bottom-up fabrication of molecular nanodevices will require precise (photo)-control over self-assembled interfacial structures. Here, the self-assembly and photopolymerization behaviors of six diacetylenic acid derivatives on highly oriented pyrolytic graphite (HOPG) surfaces are studied by using scanning tunneling microscope (STM). The van der Waals interaction among alkyl chains is the predominant driving force for determining the varied assembly structure. Diacetylenic acid derivatives with the diacetylene moiety directly connected to the carboxyl group (2,4-heptadecadiynoic acid (C17H26O2), 2,4-nonadecadiynoic acid (C19H30O2) and 2,4-heneicosadiynoic acid (C21H34O2)) assemble to form surface monolayers with lamella-like structures where the alkyl chains interdigitate. Moreover, diacetylenic acid derivatives with the diacetylene group located in the middle of the side chains and far from the carboxyl group (10,12-tricosadiynoic acid (C23H38O2), 10,12-pentacosadiynoic acid (C25H42O2) and 10,12-heptacosadiynoic acid (C27H46O2)) tend to assemble into paralleled structures with the alkyl chains adopting a tail-to-tail assembly mode. This work thus elucidates in detail the structure–function relationships for photo-modifiable self-assembled interfacial nanostructures based on diacetylenic acid.

A new type of microflowers composed of Fe 3 O 4 , reduced graphene oxide (RGO), and Ag nanoparticles (Ag NPs) was prepared by using an electrostatic self-assembly technique followed by a one-step reduction of graphite oxide and Ag + . The as-prepared composite microflowers (Fe 3 O 4 /RGO/Ag NPs) were characterized with power X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. Meanwhile, the catalytic activity of Fe 3 O 4 /RGO/Ag NPs was studied using Rhodamine B (RhB) as a degradation substrate and NaBH 4 as a reducing agent. The results indicated that the catalytic activity of Fe 3 O 4 /RGO/Ag NPs was excellent, and the degradation efficiency was up to 100% within 4 min when the loading amounts of RGO and Ag NPs were only about 1% and 1.5%, respectively. The enhanced catalytic activity of the microflowers was attributed to the synergistic effect of RGO and Ag NPs. Moreover, the catalyst can be easily recovered by using a magnet. The Fe 3 O 4 /RGO/Ag NP microflowers could be used as a high-efficiency catalyst for the degradation of hazardous dyes in wastewater.

Water-dispersible TiO2 nanoparticles with narrow size distribution and good crystallinity were synthesised in a solvothermal process using lactic acid as the capping agent. X-ray diffraction, transmission electron microscopy and nitrogen adsorption–desorption isotherm were used to characterise the products. Meanwhile, the dispersion behaviour of the as-prepared TiO2 nanoparticles was investigated. The as-prepared powder can be easily redispersed in water to form a stable solution-like suspension with a concentration of 60 mg·ml−1. Moreover, the dispersion mechanism was also preliminarily discussed, suggesting that the excellent dispersibility of the as-prepared TiO2 nanoparticles is probably because of electrostatic repulsion from lactic acid molecules covalently linked to TiO2 nanoparticles.

Rutile TiO 2 nanosheets were prepared by a simple solvothermal process, and Cu was loaded on the surface of TiO 2 nanosheets using the in situ photo-deposition method. Meanwhile, photocatalytic H 2 evolution from water over the as-prepared TiO 2 nanosheets loaded with Cu was explored using methanol as a sacrificial reagent. The results indicate that the TiO 2 nanosheets loaded with Cu is an efficient photocatalyst under UV irradiation. During the first 5 h, a rate of H 2 evolution of approximately 22.1 mmol g −1 h −1 was achieved under optimal conditions. Furthermore, for practical purposes, the photocatalytic hydrogen evolution was studied as a function of content of Cu, pH of solution, concentration of methanol and dosage of photocatalyst, respectively. At last, the photocatalytic mechanism was preliminarily discussed.

A facile approach to synthesize reduced graphene oxide (RGO) loaded potassium niobate microspheres was reported. The composition, microstructure and electron-transfer properties of the obtained product were characterized. Compared to pure potassium niobate microspheres and commercial P25 TiO2, the as-prepared potassium niobate microspheres/RGO composite showed much higher photocatalytic activity for generating hydrogen under UV irradiation. It was ascribed to the enhanced separation efficiency of electron/hole pairs as testified by electrochemical impedance spectrum and fluorescence spectrum. Importantly, the composite photocatalyst was stable and easy to recycle, and the amount of hydrogen evolution did not decrease after six recycles. The results are potentially applicable to a range of semiconductors useful in water reduction as well as other areas of heterogeneous photocatalysis.

A ternary composite photocatalyst system was prepared in a simple impregnation–pyrolysis process. In the photocatalyst system, multiwalled carbon nanotubes (MWNTs) acted as a catalyst and carrier, CuO and Cr 2 O 3 acted as a co-catalyst and/or charge transferring site, and eosin Y acted as a sensitizer. Under visible light irradiation, activity of hydrogen evolution over the system (CuO/Cr 2 O 3 –MWNTs–eosin Y) was higher than that of CuO or Cr 2 O 3 loaded MWNTs–eosin Y. It was demonstrated that simultaneous loading of CuO and Cr 2 O 3 was vital to achieve the high activity.

Cu2O loaded reduced graphene oxide (Cu2O/RGO) was prepared via a one-step in-situ reduction method. Composition and structure of the Cu2O/RGO were characterized by X-ray diffraction, high resolution transmission electron microscope and X-ray photoelectron spectroscopy. With eosin Y (EY) and rose bengal (RB) as co-sensitizers, the activity of hydrogen evolution over the Cu2O/RGO dramatically increased and achieved a maximum when the loading amount of Cu on the RGO was about 3 wt.%. It exceeded that of RGO and Cu2O by a factor of 7.3 and 4.2 at the same conditions, respectively. It could be even comparable to that of the Pt/RGO under the same reaction conditions. This work showed a possibility of utilizing Cu2O as an alternative for noble metals (such as Pt) due to its low cost and high performance in photocatalytic hydrogen production.

TiO2 nanoparticles modified with 5-(p-hydroxylphenyl)-10,15,20-triphenylporphyrin (HTPP), 5-(p-hydroxylphenyl)-10,15,20-triphenylporphyrin zinc (ZnHTPP) and trans-dichloro-5-(p-hydroxylphenyl)-10,15,20-triphenylporphyrin tin (SnHTPP) were prepared in order to improve the visible photocatalytic activity of TiO2 nanoparticles. The photocatalytic activity of the modified TiO2 nanoparticles was investigated by carrying out the photodegradation of methyl orange in aqueous solution under visible light irradiation. The TiO2 nanoparticles modified with SnHTPP show the highest visible photocatalytic activity with a degradation ratio of 86% of methyl orange after 180 min irradiation among three catalysts. This result indicates that the central metal ions in porphyrins can significantly influence the sensitization efficiency of porphyrins. In addition, the photoelectrochemical behavior of the modified TiO2 nanoparticles was examined and related to their photocatalytic activity. Finally, the photocatalytic mechanism was discussed preliminarily.

HgS nanoparticles with adjustable dispersibility have been synthesized at the water/n-butyl alcohol interface and characterized with Xray diffraction, transmission electron microscopy. Meanwhile, the dispersibility of the asprepared HgS nanoparticles in water and nbutyl alcohol were measured, respectively. The results indicate that the cubic HgS nanoparticles could be obtained; and the dispersibility of the HgS nanoparticles can be simply tuned. When Hg (CH3COO)2 aqueous solution and nbutyl alcohol solution of thioacetamide are used, the asprepared HgS nanoparticles can be dispersed in water to form a solutionlike suspension. In contrast, when thioacetamide aqueous solution and nbutyl alcohol solution of Hg (CH3COO)2 are used, the oil dispersible HgS nanoparticles are obtained. Moreover, the mechanism about the adjustable dispersibility of HgS nanoparticles is discussed.

TiO2 microspheres were prepared in a solvothermal process without involving any templates. Meanwhile, the photocatalytic activity of TiO2 microspheres was studied using p-nitrophenol as a probe. The results indicate that the anatase TiO2 microspheres with a diameter of 1-8 μm can be obtained using this simple method. Moreover, the as-prepared TiO2 microspheres display relatively high visible photocatalytic activity with 35.6% of degradation ratio of p-nitrophenol after 150 min irradiation.

TiO2 nanotubes incorporated with Cu2O clusters (Cu2O-TiNTs) were synthesized and employed as a probe for the rapid and sensitive voltammetric determination of eugenol. The electrochemical behavior of eugenol on the electrodes modified with Cu2O-TiNTs was explored systematically using cyclic voltammetry as a function of concentration of eugenol, scan rate, Cu2O content, and calcination temperature, respectively. Furthermore, the electrochemical response mechanism on these modified electrodes was discussed preliminarily. The results indicate that the electrodes coated with Cu2O-TiNTs possess high sensitivity to eugenol with a detectable concentration of 1.3 × 10−6 mol L−1. Here, the tubular structure of TiO2 nanotubes plays a key role in the electrochemical performance of Cu2O-TiNTs. The TiO2 nanotubes serve as an electron-transfer channel to enhance the electron transfer between eugenol molecules and electrode surface. Meanwhile, the Cu2O clusters serve as a promoter to further make the electron transfer more efficient and as a stabilizer to avoid change of the tubular structure of TiO2 nanotubes during calcination.

5,10,15,20-Tetrakis(4-trimethylaminophenyl)porphyrin iodide (TAPPI) was easily assembled on the surface of graphene oxide (GO) coated polystyrene (PS) microspheres by electrostatic interactions combined with π–π interactions. In the monodisperse ternary composite with core–shell structure (PS microspheres/GO/TAPPI), effective electron transfer from excited TAPPI to GO can be achieved as evidenced by fluorescence spectra. Under continuous UV illumination, TAPPI molecules in the ternary composite displayed high UV stability compared with that of pure TAPPI. Furthermore, enhanced thermal stability could also be obtained for the ternary composite. It was possible to enhance the stability of the TAPPI molecules through conjugation of the delocalized π-electron systems between the PS microsphere supported GO and TAPPI.

ZnSe hierarchical nanostructures with high crystallinity were prepared via a solvothermal reaction at the water–oil interface without the help of templates or surfactants. X-ray diffraction, transmission electron microscope, absorption spectrum and photoluminescence spectrum were used to characterize the products. Meanwhile, a possible mechanism for the formation of the ZnSe hierarchical nanostructures is discussed. The experimental results indicate that the ZnSe hierarchical nanostructures adopt spherical flower-like morphology assembled from nanosheets and possess high crystallinity. The oil–water interface plays an important role in the formation of hierarchical nanostructures. Moreover, the ZnSe hierarchical nanostructures exhibit a narrow emission with full width at half maximum (FWHM) of approximate 13 nm.

Ag-coated C60 nanoclusters were prepared and characterized with X-ray diffraction, transmission electron microscopy and nitrogen adsorption–desorption isotherm measurement. The Ag-coated C60 nanoclusters were assembled on the glass substrate to form a thin film using the layer-by-layer technique. Meanwhile, the surface enhanced Raman scattering (SERS) of musk xylene adsorbed on the film of Ag-coated C60 nanoclusters was explored. The results indicated that the film of Ag-coated C60 nanoclusters was a unique SERS-active substrate with a detection limit of 10−9 mol L−1 for musk xylene. Furthermore, the surface enhanced mechanisms were discussed preliminarily.

TiO2 nanotubes were obtained by calcining at various temperatures. The influence of calcination temperature on the degradation activity of TiO2 nanotubes for Cr (VI) was investigated under UV light irradiation. It was found that the photocatalytic activity of TiO2 nanotubes calcinated at 350 °C was the highest. Furthermore, the photocatalytic activity of TiO2 nanotubes was higher than that of the P25 TiO2 nanoparticles. Importantly, the stability of TiO2 nanotubes for the degradation of Cr (VI) was high, and degradation efficiency can still reach 72.4% after 8 recycles. Consequently, a highly stable and active photocatalyst for degradation of Cr (VI) was achieved.

Core-shell montmorillonite-TiO2 colloids were prepared in a hydrothermal process and characterized with transmission electron microscope, powder X-ray diffraction analysis, Brunauer-Emmett-Teller analysis and UV-vis spectra. Afterwards, their photocatalytic activity was investigated under UV irradiation using methyl orange as a model contaminant. In addition, the stability of the core-shell montmorillonite-TiO2 colloids was investigated by repeatedly performing methyl orange photocatalytic degradation experiments. The results indicate the as-prepared core-shell montmorillonite-TiO2 colloids are a highly efficient photocatalyst for the degradation of organic dyes in water. And this photocatalytic activity remains almost unchanged after eight successive cycles.

The effect of grinding on the photocatalytic activity of commercial ZnO powder was explored using methyl orange as a model pollutant and the corresponding mechanism was discussed tentatively. The results indicate that the photocatalytic activity of the ZnO powder grinded decreases obviously in comprison with that of the ZnO powder untreated. This phoenomenon might be ascribed to the decrease of surface defects of ZnO induced by grinding, suggesting that the further treatment leading to the change of surface states of ZnO powder as a photocatalyst ought to be avoided.

The effect of tartaric acid on the electrochemical behavior of K3[Fe(CN)6] was investigated on bare ITO electrodes, electrodes coated with multi-walled carbon nanotubes possessing carboxyl groups (MWNT-COOHs), and electrodes coated with cyclodextrin modified multi-walled carbon nanotubes (MWNT-CDs), respectively. It is found that the molecular chirality of tartaric acid can hardly influence the electrochemical behavior of K3[Fe(CN)6] on bare ITO electrodes. When the electrodes coated with MWNT-COOHs are used, the effect of the molecular chirality becomes distinguish. In the case of the electrodes coated with MWNT-CDs, the enhanced chiral discrimination between D-tartaric acid (D-TA) and L-tartaric acid (L-TA) can be observed. The control step in the electrochemical reaction of K3[Fe(CN)6] on the electrodes coated with MWNT-CDs is deduced to be different when D-TA or L-TA is introduced into the solution, respectively. Therefore, the enhanced chiral discrimination on the electrodes coated with MWNT-CDs is probably due to the change of the control step in the electrochemical reaction of K3[Fe(CN)6] caused by the chiral recognition of cyclodextrin moieties to D-TA and L-TA.

A composite of AgIn5S8/AgInS2 was prepared in aqueous solution by a simple low temperature process using mercaptoacetic acid as capping agent and thioacetamide as sulfur source. The composite was characterized by Xray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The obtained AgIn5S8/AgInS2 composite showed high visible photocatalytic activity for the degradation of methyl orange with 97.5% of degradation efficiency of methyl orange under visible irradiation for 10 min. Under same conditions, furthermore, the AgIn5S8/AgInS2 composite displayed better stability than that of pure AgIn5S8 and AgInS2.

HgS nanoparticles were loaded on the silica microspheres by an improved layer-by-layer self-assembled technique following low temperature heat-treatment. The optical properties of HgS nanoparticles on the silica microspheres were characterized with UV-vis and fluorescence spectra. The results suggested that the HgS nanoparticles were formed on the silica microspheres, and the average size of particles was approximately 15 nm. The direct band gap of the loaded HgS nanoparticles was calculated to be 2.4 eV from the absorption spectrum, which was blue-shifted by 0.4 eV from its bulk value due to quantum size effect. The photoluminescence showed a broad emission around 440 nm from sulfur vacancies. These results indicate that the optical properties of HgS nanoparticles loaded on the silica microspheres are similar to those of free HgS nanoparticles, which is encouraging for potential applications.

CuO-decorated core-shell montmorillonite-TiO2 colloids were prepared and characterized with transmission electron microscope, powder X-ray diffraction analysis, Brunauer-Emmett-Teller analysis and UV-vis spectrua. Meanwhile, their photocatalytic activity for hydrogen evolution from water was explored under UV irradiation using methanol as a sacrificial reagent. The results indicate that they are an efficient photocatalyst with a rate of H2 evolution of 219 μmol·h-1·g-1 which is higher than that of anatase TiO2 nanoparticles.

A visible light photocatalytic system consisting of Eosin Y containing trace vitamin B12(VB12) as a light harvesting unit, multiwalled carbon nanotubes (MWCNTs) as an electron transfer channel and CuO as a hydrogen evolution center (abbreviated to Eosin Y/VB12-MWCNTs-CuO) was prepared on the basis of the synergistic effect between Eosin Y and VB12under visible light irradiation. The Eosin Y/VB12-MWCNTs-CuO system exhibits a higher photocatalytic activity of hydrogen evolution than the Eosin Y-MWCNTs-CuO system. The improvement of the photocatalytic activity is probably due to the effective transfer of photogenerated electrons and stabilization of VB12to excited Eosin Y.

A ternary assembly consisting of reduced graphene oxide (RGO), Ag nanoparticles, and polystyrene (PS) microsphere was prepared in aqueous solution by an electrostatic assembly combined with one-step reduction process. The composition and structure of the assembly (PS microsphere/RGO/Ag) were characterized by powder X-ray diffraction, transmission electron microscope, scanning electron microscope, X-ray photoelectron spectroscopy, and Raman spectroscopy. The interactions among RGO, Ag nanoparticles, and PS microsphere were investigated by surface enhanced Raman scattering spectroscopy. The results showed that there existed strong interactions among RGO, Ag nanoparticles, and PS microsphere. Importantly, the assembly showed high heat stability and good dispersion in water.

Reduced graphene oxide/potassium niobate composite nanoscrolls were prepared by incorporating reduced graphene oxide (RGO) sheets into potassium niobate sheets at room temperature. The composite nanoscrolls were characterized by X-ray diffraction, transmission electron microscopy, UV–vis diffusion reflectance spectra and fluorescence spectra. For the photocatalytic degradation of rhodamine B (RhB) under UV light, the degradation efficiency of the composite nanoscrolls can reach 68.3% after irradiation for 30 min, increased 34.3% relative to the pure potassium niobium nanotubes. The dramatically enhanced activity can be attributed to the synergistic contribution of both a retarded charge recombination rate caused by a high electronic mobility of RGO and an increased surface adsorption of RhB.

Monodispersed AgIn 5 S 8 microspheres were synthesized using a one-pot solution method and characterized with X-ray diffraction, UV–vis diffuse reflectance spectroscopy, scanning electron microscope, energy dispersive X-ray spectroscopy and N 2 adsorption–desorption isotherm. The results indicated that the AgIn 5 S 8 microspheres were of cubic spinel structure and the mean diameter of about 0.5 μm. In addition, the visible light photocatalytic activity of AgIn 5 S 8 microspheres was also investigated at room temperature. The AgIn 5 S 8 microspheres showed very high photocatalytic activity for the degradation of methyl orange with a degradation efficiency of about 98% under visible light irradiation for 20 min.

A series of nanostructured Zn2GeO4 were prepared in a low temperature solvothermal process and characterized with transmission electron microscopy and X-ray diffraction. Then, the formation mechanism of nanostructured Zn2GeO4 was discussed. At last, their electrochemical behavior was investigated. The results indicate that the Zn2GeO4 nanorods can exhibit more excellent electrochemical activity.

Highlights: ► Mesoporous TiO{sub 2} hollow spheres were prepared in a one-pot process. ► The process does not involve any templates and surfactants. ► The TiO{sub 2} hollow spheres display high photocatalytic activity. -- Abstract: Mesoporous TiO{sub 2} hollow spheres were prepared in a solvothermal process, which did not involve any templates and surfactants. Meanwhile, the photocatalytic activity of TiO{sub 2} hollow spheres was studied using methyl orange as a probe. The results indicate that the anatase TiO{sub 2} hollow spheres with mesoporous walls and high specific surface area (141 m{sup 2} g{sup −1}) can be obtained using this simple method. The mean diameter and wall thickness of spheres are about 700 nm and 90 nm, respectively. Moreover, the as-prepared TiO{sub 2} hollow spheres display high photocatalytic activity with 98% of degradation ratio of methyl orange after 30 min irradiation.

In the present work, SnSe nanosheets were prepared via a reaction at the oil–water interface in the solvothermal process at low temperature (130 °C), which did not involve any templates and amines such as oleylamine. X-ray diffraction, transmission electron microscope, absorption spectrum and nitrogen adsorption were used to characterize the products. The results indicated that the SnSe nanosheets obtained adopted a square-like morphology with lateral dimensions of approximately 120 nm × 120 nm and possessed high crystallinity. Moreover, their electrochemical performance, as an anode material, was evaluated by galvanostatic discharge–charge tests, showing that the as-prepared SnSe nanosheets exhibited a high initial discharge capacity of 1009 mA h g −1 as a potential energy storage material.

A composite photocatalyst containing Eosin Y as a sensitizer, multiwalled carbon nanotubes as a supporter material or electron transfer channel, and CuO/NiO as an active center of H 2 evolution from water was fabricated and characterized with X-ray photoelectron spectroscopy and transmission electron microscope. Meanwhile, photocatalytic hydrogen evolution from water over this catalyst was explored using triethanolamine as a sacrificial reagent under visible irradiation. A rate of H 2 evolution of approximately 1.0 mmol g −1 h −1 was achieved under optimal conditions. Furthermore, for practical purposes, the photocatalytic hydrogen evolution was studied as a function of content of CuO/NiO, mass ratio of CuO to NiO, pH of solution, concentration of triethanolamine and dosage of Eosin Y, respectively. The results show that mixed metal oxides are a kind of promising active centers of H 2 evolution from water in the photocatalytic system studied.

Quasi-monodispersed Cd x Zn 1− x S nanocrystals were prepared in a solvothermal process and characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersion X-ray analysis (EDX), UV–vis diffuse reflectance absorption spectra and photoluminescence spectra. The results showed that the uniform Cd x Zn 1− x S nanocrystals with narrow size distribution could be obtained using laurylamine as solvent; and the mean diameter was 2.8 nm. Meanwhile, it was also found that the band gap energies and the fluorescence emission peaks of as-prepared Cd x Zn 1− x S nanocrystals systematically shifted to shorter wavelength with increasing Zn content. The Cd 0.5 Zn 0.5 S nanocrystals can exhibit obviously upconversion emission due to two-photon excitation. In addition, the preparation and properties of Cd x Zn 1− x S nanocrystals were studied as functions of reaction time and reaction temperature, respectively.

We developed a facile method to prepare CdIn 2 S 4 monodispersed spherical particles by using mercaptoacetic acid as capping agent and thioacetamide as sulfur source. The results indicated that the size and morphology of CdIn 2 S 4 particles were related to reaction time. The CdIn 2 S 4 spherical particles with an average size of about 236 nm and a narrow size distribution were formed after reacting for 7 h. The photocatalytic activity of as-synthesized CdIn 2 S 4 spherical particles was evaluated by the photocatalytic degradation of methyl orange under visible light illumination. The results showed that the photocatalytic activity increased with prolonging reaction time in the preparation of CdIn 2 S 4 spherical particles. The CdIn 2 S 4 spherical particles prepared after reacting for 7 h exhibited a 98% degradation efficiency of methyl orange after 15 min visible light irradiation.

Titanate nanotubes (TNTs) co-sensitized with CdS nanoparticles and 5-(4-hydroxyphenyl)-10,15,20-triphenylporphyrin zinc (ZnMOHPP) were prepared by a simple process. In the co-sensitized TNTs, CdS nanoparticles were anchored on the surface of TNTs by an in-situ ion-change reaction, and ZnMOHPP molecules were linked on the surface of TNTs by interaction of hydroxyl groups. Importantly, the co-sensitized TNTs possessed excellent light-harvesting, efficient separation of the photogenerated charges and higher visible-light photocatalytic activity. It was attributed to the complementary absorption and the intimate anchoring between TNTs and co-sensitizers.

Cobalt (II) tetrakis (4-sulfonatophenyl) porphyrin (CoTPPS) was axially coordinated with amino-modified multi-walled carbon nanotubes (MWCNT) to form a MWCNT-CoTPPS hybrid. The hybrid was drop cast on the glassy carbon electrode (GCE) to obtain MWCNT-CoTPPS/GCE. The structure of the MWCNT-CoTPPS hybrid was characterized by field-emission transmission electron microscope. X-ray photoelectron spectroscopy was also conducted to characterize the MWCNT-CoTPPS hybrid. Cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry were used to evaluate the electrocatalytic activity of MWCNT-CoTPPS/GCE for the oxidation of nitric oxide (NO). The effects of potential scan rate, temperature and NaNO 2 concentration on the electrochemical oxidation of NO at the MWCNT-CoTPPS/GCE were studied in detail. The obtained MWCNT-CoTPPS/GCE demonstrated a potential application for detecting NO in aqueous solution.

Si-doped TiO 2 nanoparticles with anatase crystalline phase were prepared by a hydrothermal method using acetic acid as the solvent. Photoelectrochemical studies showed that the photocurrent value for the 15% Si-doped TiO 2 electrode (54.4 μA) was much higher than that of the pure TiO 2 electrode (16.7 μA). In addition, the 15% Si-doped TiO 2 nanoparticles displayed the highest photocatalytic activity under ultraviolet light irradiation. So doping suitable amount of Si in TiO 2 nanoparticles was profitable for transferring photogenerated electrons and inhibiting the recombination of photogenerated electrons and holes. As a result, the photocatalytic activity of TiO 2 nanoparticles was improved.

Multiwalled carbon nanotubes (MWNTs) as a usual supporter were directly used as a visible light photocatalyst for the degradation of methyl orange (MO) in aqueous solution. The MWNTs exhibited high photocatalytic activity for the degradation of MO under visible light irradiation. Moreover, the photocatalytic activity of MWNTs was greatly enhanced when Pt nanoparticles were loaded on the surface of MWNTs. In order to understand the photocatalytic behavior of MWNTs, the electrochemical impedance spectra and the adsorption characterization of MWNTs were investigated. On the basis of these experiments, a possible visible light photocatalytic degradation mechanism was discussed.

The multiwalled carbon nanotubes modified with hydroxyl groups were prepared in deoxygenated tetrahydrofuran using sodium zincate as an electrophilic reagent. NaOH solution and Zn powder were mixed to synthesize sodium zincate. The multiwalled carbon nanotubes were covalently modified with hydroxyl groups by the reaction between sodium zincate and multiwalled carbon nanotubes under sonication at room temperature. The product was characterized with FT-IR spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscope. The results indicate that the multiwalled carbon nanotubes are readily modified with hydroxyl groups, and their diameter and morphology are well retained. Moreover, the multiwalled carbon nanotubes modified with hydroxyl groups can be highly dispersed in ethanol to form a uniform and stable solution.

A stable metalloporphyrin sensitized TiO2 (Degussa P25) photocatalyst was prepared by using trans-dihydroxo[5,10,15,20-tetraphenylporphyrin]tin(IV) (SnP) as a sensitizer in a simple impregnation process. The solid diffuse reflectance ultraviolet-visible (UV-vis) spectrum of the SnP sensitized TiO2 photocatalyst (SnP-TiO2) indicated that there existed interaction between SnP and TiO2. It was found that SnP-TiO2 exhibited an enhanced visible light photocatalytic activity as compared with that over P25 for the degradation of 4-nitrophenol (4-NP) and methyl orange (MO) in aqueous solutions. The mechanism exploration showed that the degradation of MO and 4-NP experienced two different ways, that is, MO was photodegraded by reactive oxygen species and 4-NP was directly photodegraded by the excited state of SnP. Furthermore, it was found that the loading content of SnP had an important influence on the photocatalytic activity of TiO2. The maximum photocatalytic efficiency was achieved when the contents of SnP we...

CdS nanoparticles were prepared and simultaneously loaded on the ion exchange resin microspheres via a simple in-situ gas-solid reaction. X-ray diffraction (XRD), scanning electron microscope (SEM), EDX analysis and UV-vis spectra were used to characterize the products. The results indicated that the CdS nanoparticles were loaded on the ion exchange resin microspheres, and the average size of particles was approximately 5.3 nm. The nanoparticle coverage was high so that a continuous nanoparticle shell formed on the ion exchange resin microspheres. In addition, the effect of Pb2+ ions (aq.) on the luminescence of the CdS nanoparticles immobilized on the ion exchange resin microspheres were investigated. It was found that the luminescence intensity of the CdS nanoparticles changed significantly when Pb2+ ions were adsorbed on the sample. The lowest concentration of Pb2+ ions that can make the intensity change is 1.0´10-20 mol×dm-3, which implies that the CdS nanoparticles immobilized on the ion exchange resin microspheres are very sensitive to Pb2+ ions (aq.).

The visible-light photocatalytic activity of titanate nanotubes (TiNTs) sensitized by 5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetraphenylporphyrin manganese (MnTPP), 5,10,15,20-tetraphenylporphyrin nickel (NiTPP) and 5,10,15,20-tetraphenylporphyrin zinc (ZnTPP), respectively, was investigated by the photocatalytic degradation of methyl orange (MO) as a probe reaction. The results showed that the central ions of porphyrins had an important influence on the photocatalytic activity of the samples. The activity was in the order of TiNTs-ZnTPP > TiNTs-TPP > TiNTs-NiTPP > TiNTs-MnTPP. Combined the result of absorption spectra with that of fluorescence spectra, it was demonstrated that various visible-light absorption and photoelectron transfer caused by the central ions of porphyrins were the decisive factor for the visible-light photocatalytic activity of the sensitized TiNTs.