[en] 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.

[en] Graphical abstract: A dense CuGaS_2 ultrathin film was prepared in an improved layer-by-layer self-assembled process following heat treatment. And, the as-prepared CuGaS_2 ultrathin film possesses high sensitivity to L-noradrenaline. - Highlights: • Tetragonal CuGaS_2 film was prepared in a simple process. • CuGaS_2 film exhibits a narrow emission. • High sensitivity to LNE with a detection limit of 2.83 ng cm"−"2. - Abstract: A dense CuGaS_2 ultrathin film was prepared in an improved layer-by-layer self-assembled process followed by heat treatment and characterized with X-ray diffraction, scanning electron microscopy, UV–vis spectroscopy, and fluorescence spectroscopy. Meanwhile, the application of the as-prepared CuGaS_2 ultrathin film in the trace detection of L-noradrenaline was explored as a photoluminescent probe. The results show that the tetragonal phase CuGaS_2 film fabricated on the glass substrate is smooth and dense. And this CuGaS_2 ultrathin film can exhibit a strong emission at 829 nm with full width at half maximum of approximate 12 nm. Furthermore, the as-prepared CuGaS_2 ultrathin film possesses high sensitivity to L-noradrenaline with a detectable concentration of 2.83 ng cm"−"2 when it is used as a photoluminescent probe, implying that it is a promising candidate in the field of biological and chemical sensing in future.

[en] In the present work, “water dispersible” TiO_2 nanoparticles were prepared, and meanwhile, their photocatalytic activity was systematically tested for the reduction of aqueous Cr(VI) ions. It is found that the as-prepared “water dispersible” TiO_2 nanoparticles are a highly efficient photocatalyst for the reduction of Cr(VI) ions in water under UV irradiation, and suitable for the remediation of Cr(VI) ions wastewater with low concentration. Compared with commercial TiO_2 nanoparticles (P25), the “water dispersible” TiO_2 nanoparticles exhibit 3.8-fold higher photocatalytic activity. 100% Cr (VI) ions can be reduced into Cr(III) ions within 10 min when the Cr (VI) ions initial concentration is 10 mg L"−"1. Moreover, the electrical energy consumption can be obviously decreased using the “water dispersible” TiO_2 nanoparticles. These results suggest that the “water dispersible” TiO_2 nanoparticles are a promising photocatalyst for rapid removal of Cr (VI) in environmental therapy. - Highlights: • “Water dispersible” TiO_2 nanoparticles with high photocatalytic activity. • 100% Cr (VI) (10 mg L"−"1) can be reduced within 10 min. • Obvious decrease of electrical energy consumption.

[en] It is of great significance for the large-scale application of photocatalytic hydrogen (H₂) production technology to develop an efficient, stable and noble metal free photocatalyst. Here, we developed a photocatalytic system consisting of Ti₃C₂ quantum dots embedded in TiO₂ nanosheets and CuWO₄ nanoparticles and then investigated its photocatalytic activity for H₂ generation. Finally, its photocatalytic mechanism was discussed generally. It was found that this photocatalytic system is an efficient noble metal free photocatalyst for H₂ production. Under its catalysis, the H₂ production rate can be up to 3.65 mmol g^-1 h^-1, which is 192 times as high as that over TiO₂ nanoparticles (P25). Moreover, this photocatalytic system also possesses excellent stability. After nine cycles, it can even exhibit stronger photocatalytic activity in comparison with the fresh one. Thus, it was found that the Ti₃C₂ quantum dots embedded in the TiO₂ nanosheets possess great potential as a photocatalytic platform. This will provide a new ideas for the design and development of novel noble metal free TiO₂-based photocatalysts in the future. (authors)

[en] Highlights: • Preparation of Co₃O₄/CoP composite hollow polyhedrons. • Application of Co₃O₄/CoP composite in 4-nitrophenol reduction. • High catalytic activity for the borohydride-assisted reduction of 4-nitrophenol. • High catalytic stability of Co₃O₄/CoP composite hollow polyhedrons. In the present work, Co₃O₄/CoP composite hollow polyhedrons were prepared and characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and N₂ adsorption-desorption isotherms. Then, the catalytic activity of the as-prepared Co₃O₄/CoP hollow polyhedrons was evaluated for the borohydride-assisted reduction of 4-nitrophenol at room temperature. The results indicate that the as-prepared Co₃O₄/CoP hollow polyhedrons are an efficient recyclable catalyst for the reduction of 4-nitrophenol. When the 4-nitrophenol initial concentration is 1.0 × 10⁻⁴ mol L⁻¹ (100 mL), almost 100% 4-nitrophenol can be reduced within 3 min in the presence of the Co₃O₄/CoP hollow polyhedrons. The apparent rate constant of the 4-nitrophenol reduction is 1.61 min⁻¹ at room temperature, and the activity factor is about 5.37 × 10⁴ mL min⁻¹ g⁻¹, which is almost two times higher than that over Ag nanoparticles. Finally, the catalytic mechanism was preliminarily discussed. It is found that CoP plays an important role in the catalytic process. Here, CoP serves as active sites, which leads to efficient formation of hydrogen atoms from BH₄⁻ and fast electron transfer.

[en] CuWO_4-x nanoparticles incorporated brookite TiO₂ porous nanospheres were prepared and investigated for photocatalytic light driven H₂ generation. The as-prepared nanospheres are an efficient and stable noble metal-free photocatalyst for H₂ production. The highest H₂ evolution rate is 9.85 mmol g⁻¹ h⁻¹, which is 25 times as high as that over the commercial TiO₂ nanoparticles (P25, 0.39 mmol g⁻¹ h⁻¹). This dramatic photocatalytic activity may be mainly attributed to the following two aspects: (1) the superior separation of the electro-hole pair caused by efficient charge transfer between TiO₂ matrix and CuWO_4-x nanoparticles which follows a Z-scheme-like mechanism, and (2) large specific surface area and abundant micropores. Moreover, also the stability of the as-prepared TiO₂ nanospheres is satisfactory. After two consecutive runs, the photocatalytic activity is still about 90 percent of the initial photocatalytic activity.

[en] Highlights: • A special hydroxylporphyrin/NiO nanosheets photocatalytic system was achieved. • The materials possessed high light absorption and strong interfacial interaction. • The photocatalytic system was greatly active and stable for H₂ production. • The mechanisms of assembly and photo-produced electron transfer were investigated. Hexagonal nickel oxide nanosheet (NiO) was surface modified with various amounts of tetrahydroxylphenyl porphyrin (THPP) to form a series of THPP/NiO nanosheet photocatalysts. The interacted mechanism between THPP and NiO was studied in detail by ultraviolet spectroscopy and fluorescence spectroscopy. Furthermore, the photocatalytic activity for hydrogen production and electron transfer mechanism over the THPP/NiO nanosheet nanocomposite were investigated by fluorescence spectra, UV–vis spectra and electrochemical measurements. The results showed that the special coordination interaction between THPP and NiO had an important influence on the photocatalytic performance of the nanocomposite, and a photocatalyst with high and stable photocatalytic activity can be achieved by controlling the interaction between porphyrin and NiO-like metal oxides. It will provide a new idea for fabricating highly efficient photocatalysts for hydrogen production.

[en] Highlights: • Controlled growth of AgNPs on porous Cu₂O@SiO₂@ZIF-8 was facilely achieved. • There exists a strong interaction between AgNPs and ZIF-8 in the Cu₂O@SiO₂@ZIF-8. • SERS detection of phenol red has a close relationship with the size of AgNPs. • 4 nm AgNPs embedded Cu₂O@SiO₂@ZIF-8 showed a lower detection limit for phenol red. • Contaminants containing polyaromatic structures with N or S group can be detected. Using 5-mercapto-1-methyltetrazole as the bridge, a porous (~4 nm) Zn metal–organic frameworks coated cuprous oxide/silica core–shell nanostructure (Cu₂O@SiO₂@ZIF-8) was facilely fabricated. Subsequently, using it as a template, the precisely controlled growth of AgNPs with various sizes (2 nm~29 nm) was achieved. It was found that a strong interaction between AgNPs and ZIF-8 in the Cu₂O@SiO₂@ZIF-8 favored the AgNPs to be uniformly distributed in the Cu₂O@SiO₂@ZIF-8. When more AgNPs were obtained in the cavity of Cu₂O@SiO₂@ZIF-8 with large surface areas (~568.95 m²/g), higher SERS response towards phenol red was resulted in. Moreover, 4 nm AgNPs embedded Cu₂O@SiO₂@ZIF-8 substrate showed a lower limit of detection (5.76 × 10^-12 mol·L^-1) and limit of quantification (1.92 × 10^-12 mol·L^-1), and a higher enhancement factor of 1.7 × 10⁷. Additionally, Raman activity of the Cu₂O@SiO₂@ZIF-8@Ag changed little within 35 days, and also the low concentration of phenol red in actual sample can be detected. Therefore, the Cu₂O@SiO₂@ZIF-8@Ag could be employed as highly sensitive and continuously stable 3D substrate for SERS detection of environmental contaminants.

[en] Highlights: • The AuNPs/glycine derivatives (G_n)/GQDs composites with tunable bi-functionalities were fabricated. • The fluorescence and SERS response could be tuned effectively by changing the chain length of G_n. • This composite could be used in a wide pH range and exhibited good stability. • This composite displayed low cytotoxicity in A549 cells. Controllable assembly of the hybrids composed of various types of nanoscale objects provides new opportunities for material fabrication. Herein, the tunable bi-functionalities of fluorescence and surface enhanced Raman scattering (SERS) signals were collected by the assembled composites of gold nanoparticles (AuNPs)/glycine derivatives (G_n, n = 0, 3, 4, 5, 6 and 9)/graphene quantum dots (GQDs). The composition and structure of the AuNPs/G_n/GQDs composites were characterized by Fourier-transform infrared (FT-IR) spectroscopy and high resolution transmission electron microscope (HRTEM). Results indicated that the fluorescence and SERS response could be tuned effectively by changing the chain length of G_n. Also, the AuNPs/G_n/GQDs composites could be used in a wide pH range and exhibited good stability at room and physiological temperatures. Moreover, the AuNPs/G_n/GQDs composites displayed low cytotoxicity in A549 cells, and the cell viability was found to be above 90% at concentrations ranging from 6.42 to 200 μg/mL, which made AuNPs/G_n/GQDs composites very attractive for biological imaging applications in vivo.

[en] In this work, SiO₂ nanoparticles were prepared via hydrolysis method, chemical precipitation method and sol-gel method, respectively. And the effects of various experimental conditions on the unit output, yield, particle size and size distribution of SiO₂ nanoparticles were studied and parameterized. Meanwhile, a set of evaluation systems were constructed with fuzzy mathematical analysis and modeling which the complex data can be evaluated systematically with concise and precise unity. The results indicate that Si and Na₂SiO₃ are suitable raw materials for the industrial production of 20 nm and 60 nm SiO₂ nanoparticles and the maximum weighted average can reach the high level of 81.3 and 82.95, respectively. Also, SiO₂ nanoparticles with 250 nm ought to be prepared using TEOS as the raw material, and its maximum weighted average is 85. Moreover, the results also show that the order of the effects of the factors in hydrolysis is the dosage of sodium silicate > the amount of silica powder > the reaction time. For the chemical precipitation method, the order is the pH value > the reaction time > the reaction concentration. For the sol-gel method, the order is the amount of ammonia water > TEOS consumption > the reaction time. (paper)