Strain-Induced Photocatalytic H2 Production over BiVO4 in Pure Water without Any Cocatalyst.

In this study, BiVO4 nanosheets (BiVO4-NS) were prepared by a facile hydrothermal method. It is found that sonication-induced strain can effectively promote the H2 production over BiVO4-NS in the presence of pure water without any cocatalysts. With the assistance of the sonication, the H2 production over BiVO4-NS is 1.344 mmol·g-1 after 3 h simulated sunlight irradiation, which is 24.8 times higher than that of BiVO4-NS without sonication (0.054 mmol·g-1). In addition, the products of water oxidation are determined to be hydroxyl radicals and hydrogen peroxide. Moreover, BiVO4-NS also shows obviously enhanced photoactivity than that of the commercially available BiVO4 nanoparticles (BiVO4-C). The improved photoactivity of BiVO4-NS is attributed to the effective charge separation and low charge transfer resistance. The underlying mechanism of sonication-promoted water splitting is investigated by a variety of controlled experiments. The results show that ultrasonic waves can produce obvious strain inside the sample, which results in lattice distortion of BiVO4. Therefore, the conduction band of BiVO4 is obviously negative shifted, which is beneficial for H2 production. In addition, the strain in BiVO4 also produces local polarization of the sample, which effectively promotes the charge transfer and separation process. It is hoped that our study could provide a new strategy for achieving efficient photocatalytic water splitting.

Amino-functionalized MIL-125(Ti) for photodenitrification of pyridine in fuels via coordination activation by unsaturated Ti4+ centers.

Due to their explicit structure, metal-organic frameworks (MOFs) have been supposed to be credible platforms to research the micro-mechanism of heterogeneous photocatalysis. In this study, amino-functionalized MOFs (MIL-125(Ti)-NH2 (denoted as MTi), UiO-66(Zr)-NH2 (denoted as UZr) and MIL-68(In)-NH2 (denoted as MIn)) with three different metal centers were synthesized and applied for the denitrification of simulated fuels under visible light irradiation, during which pyridine was used as a typical nitrogen-containing compound. The results showed that MTi had the best activity among the above three MOFs, and the denitrogenation rate increased to 80% after 4 h of visible light irradiation. On the grounds of the theoretical calculation of pyridine adsorption and actual activity experiments, it can be presumed that the unsaturated Ti4+ metal centers should be the key active sites. Meanwhile, the XPS and in situ infrared results verified that the coordinatively unsaturated Ti4+ sites facilitate the activation of pyridine molecules through the surface -N⋯Ti- coordination species. The coordination-photocatalysis synergism promotes the efficiency of photocatalytic performance and the corresponding mechanism is proposed.

Characterization, stability and antioxidant activity of curcumin nanocomplexes with soy protein isolate and pectin.

Curcumin (Cur) has antioxidant, anti-inflammatory and other biological activities, but its poor stability, low water solubility and other defects limit the application. Herein, Cur was nanocomposited with soy isolate protein (SPI) and pectin (PE) for the first time and its characterization, bioavailability and antioxidant activity were discussed. The optimal encapsulation process of SPI-Cur-PE was as follow: the addition amount of PE was 4 mg, Cur was 0.6 mg and at pH of 7. It was observed by SEM that SPI-Cur-PE were partially aggregated. The average particle size of SPI-Cur-PE was 210.1 nm and the zeta potential was -31.99 mV. Through XRD, FT-IR and DSC analysis, the SPI-Cur-PE was formed through hydrophobic interaction and electrostatic interaction. The SPI-Cur-PE released more slowly in simulated gastrointestinal treatment and displayed higher photostability and thermal stability. SPI-Cur-PE, SPI-Cur and free Cur had scavenging activities for 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals.

Spatial Separation of Electrons and Holes among ZnO Polar {0001} and {101Ì 0} Facets for Enhanced Photocatalytic Performance.

Spatial separation of electrons and holes is critical for improving their photocatalytic performance, which is ascribed to the suppressed photoinduced carriers' recombination among facets. In this work, the ZnO-Au-MnO x heterogeneous nanostructure photocatalyst was prepared by photodepositing Au and MnO x on the ZnO polar {0001} and {101̅0} crystal facets, respectively. The photocatalytic performance of ZnO-Au-MnO x was higher than ZnO and ZnO-Au for the degradation of rhodamine B dye under UV light irradiation. Due to the potential difference between different crystal planes of zinc oxide, electrons and holes will migrate to different crystal planes of zinc oxide. This will lead to the deposition of Au and MnO x on different crystal facets of zinc oxide. The efficient photoinduced carrier separation of ZnO-Au-MnO x resulted in the high photocatalytic activity, which is well supported by photoelectrochemical and photoluminescence analyses. The intermediated species formed during the reaction were investigated by high performance liquid chromatography. The reaction mechanism was investigated by radical trapping experiments and electron spin resonance analysis. The special structure of selective deposition of redox cocatalysts on the different facets should be promising and intriguing for designing highly efficient photocatalysts.

Spatial variation of volatile organic compounds and antioxidant activity of turmeric (Curcuma longa L.) essential oils harvested from four provinces of China.

The objective of this study was to investigate the spatial variation of volatile organic compounds and antioxidant activity of turmeric essential oils (TEOs) harvested from four provinces of China. The major chemical components of these TEOs were analyzed using headspace solid-phase micro-extraction gas chromatography-mass spectrometry. More than forty volatile organic compounds in TEOs were identified, which accounted for 82.09-93.64% of the oil components. The relative abundances of the main volatile organic compounds in TEOs at the genus level were visualized by a heat map. The antioxidant activity of the TEOs of five different origins was characterized by the DPPH free radical scavenging activity, in which the antioxidant activity of the TEOs from Guangxi was superior to those of other sources. Furthermore, the IC50 values of the antioxidants TEOs collected from Guangxi, Sichuan, Yunnan, Changting, and Liancheng were 33.30, 42.5, 35.22, 63.27, and 39.96 mg/mL, respectively, which indicated the excellent free radical scavenging activity of those TEOs. Therefore, the TEOs might be considered as a natural antioxidant with potential applications in food and pharmaceutical industries.