ABSTRACT
Selective oxidation of methane to methanol has been often considered as a "holy grail" reaction in catalysis. Herein, we systematically investigate the effect of solution pH and Pd-to-Au ratio of AuPd x colloid on the catalytic performance of methane oxidation. It is revealed that these two parameters can determine the amount of H2O2 participated in the reaction, which is linearly related to the productivity of oxygenates. A high catalytic performance in methane activation requires a high utilization of H2O2 to generate more ·OH. The optimal pH is 3.0 and the optimal Pd-to-Au ratio is between 0.1 to 0.7.
ABSTRACT
Heterostructural engineering and three-dimensional architecture construction are effective strategies to optimize the photocatalytic performance of semiconductors. Herein, we integrate these two strategies and controllably synthesize ZnO-BiOI heterostructures with well-defined architectures. Microstructural and surface analysis reveals that the strong electronic interaction between ZnO and Bi3+ ensures a bounded nucleation and growth of BiOI on the surface of ZnO, which leads to the formation of ZnO-BiOI nanorod heterostructures (ZnO-BiOI-NR) with very high dispersion of BiOI on ZnO nanorods. In contrast, when the nucleation and growth of BiOI occurs before reacting with ZnO nanorods, ZnO-BiOI heterostructures (ZnO-BiOI-NF) are composed of BiOI nanoflowers (NFs) and ZnO nanorods. The precise control over the interfaces of ZnO-BiOI heterostructures provides ideal models to investigate the influence of the interfaces on the catalytic performance of heterostructures. It is important to highlight that the photocatalytic activity of ZnO-BiOI-NR is 12 times higher than that of ZnO-BiOI-NF. Mechanism studies suggest that the abundant ZnO-BiOI interfaces in ZnO-BiOI-NR benefit the generation and separation of hole-electron pairs, which consequently improve the catalytic performance.
ABSTRACT
Gastric cancer is the fourth most common malignancy globally. In order to decrease the dosage and side effects of conventional chemotherapy, and achieve improved benefits from molecular targeted therapy, novel drug delivery systems were developed in the present study. Oxaliplatin-Au-Fe3O4-Herceptin® acts as a dual-functional nanoparticles (NPs) conjugate and possesses the capability of human epithelial growth factor receptor 2 (HER2) targeting and oxaliplatin delivery. The 8-20 nm Au-Fe3O4 were synthesized by decomposing iron pentacarbonyl on the surfaces of Au NPs in the presence of oleic acid and oleylamine. Following being coated with polyethylene glycol, the NPs possessed a ζ-potential of 13.8±1.6 mV and were demonstrated to exhibit no cytotoxicity when Fe concentration is <100 µg/ml via an MTS assay. Mass spectrometry analysis detected a peak at m/z 148,000, and Nuclear Magnetic Resonance indicated peaks at δ 3.51 (8.00H, s, 3-H), 2.97-3.02 (3.80H, t, 2-H) and 2.72-2.76 (3.72H, t, 1-H) following successful loading with Herceptin and oxaliplatin probes. A drug release assay via dialysis cassettes demonstrated that 25% of the oxaliplatin was released at pH 8.0, however >58% was released at pH 6.0 following 4 h incubation, indicating its pH-dependent release characteristic. The active targeting feature of oxaliplatin-Au-Fe3O4-Herceptin was verified in a subcutaneous xenograft mouse model containing SGC-7901 cells via detecting aggregated low intensity in T2-weighted magnetic resonance imaging, which was further confirmed by immunohistochemistry. Therefore, oxaliplatin-Au-Fe3O4-Herceptin is a promising multifunctional platform for simultaneous magnetic traceable and HER2 targeted chemotherapy for gastric cancer.
ABSTRACT
Fast optimization of mesoporous ternary metal oxide (CuCeZrO(w)) catalysts for n-hexane oxidation is achieved via a newly developed combinatorial approach based on ink-jet printing assisted synthesis and multi-dimensional group testing.
ABSTRACT
A thermal and hydrothermal stable mesoporous ceramic acid (mCA) was synthesized by uniform coating of a WZrO(x) layer onto the internal surface of extra-large mesoporous silica (EP-FDU-12). Its ordered mesoporous structure and strong Brönsted acid sites display excellent thermal (1000 °C, air, 5 h) and hydrothermal (water steam, 300 °C, 24 h) stability.
