Efficient Photocatalytic Degradation of RhB by Constructing Sn3O4 Nanoflakes on Sulfur-Doped NaTaO3 Nanocubes

Band structure engineering and heterojunction photocatalyst construction are efficient approaches to improve the separation of photo-induced electrons and holes, along with enhancing light response ability. By sulfur doping, sodium tantalite (NaTaO3) showed an improved photocatalytic property for the degradation of Rhodamine B (RhB). Sn3O4 nanoflakes were constructed on the surface of NaTaO3 nanocubes, forming a surface heterostructure via a simple hydrothermal process, initially. This heterostructure endows the photocatalyst with an enhanced charge separation rate, resulting in an improved photocatalytic degradation of RhB. Moreover, a possible mechanism over Sn3O4/NaTaO3 and the photodegradation pathway of RhB were proposed as the combined effect of photo-induced electrons and holes. This facile process for band structure engineering and heterostructure construction provides the possibility for the practical application of high-efficiency photocatalysts

Efficient Photocatalytic Degradation of RhB by Constructing Sn₃O₄ Nanoflakes on Sulfur-Doped NaTaO₃ Nanocubes

Band structure engineering and heterojunction photocatalyst construction are efficient approaches to improve the separation of photo-induced electrons and holes, along with enhancing light response ability. By sulfur doping, sodium tantalite (NaTaO3) showed an improved photocatalytic property for the degradation of Rhodamine B (RhB). Sn3O4 nanoflakes were constructed on the surface of NaTaO3 nanocubes, forming a surface heterostructure via a simple hydrothermal process, initially. This heterostructure endows the photocatalyst with an enhanced charge separation rate, resulting in an improved photocatalytic degradation of RhB. Moreover, a possible mechanism over Sn3O4/NaTaO3 and the photodegradation pathway of RhB were proposed as the combined effect of photo-induced electrons and holes. This facile process for band structure engineering and heterostructure construction provides the possibility for the practical application of high-efficiency photocatalysts

Synthesis and characterization of lithium niobium borate glasses containing neodymium

A series of (90–x)Li2B4O7-10Nb2O5-xNd2O3 glass samples (x=0, 5 mol.%, 10 mol.%, 15 mol.%, 20 mol.% and 25 mol.%) were synthesized using melt quenching technique. X-ray diffraction (XRD), differential thermal analyzer (DTA), Fourier transformed infrared (FTIR), ultraviolet-visible-near-infrared (UV-Vis-NIR) spectrometer and photoluminescence (PL) spectroscopic characterizations were made to examine the influence of Nd3+ concentration on the physical, structural and optical properties. Various physical properties such as glasses density, molar volume, thermal stability, ion concentration, polar on radius, inter-nuclear distance, field strength, cut-off wavelength, energy band gap and Urbach energy were calculated. The samples were amorphous in nature and confirmed from XRD pattern. The FTIR spectra revealed the presence of BO3 and BO4 functional groups. UV-Vis-NIR spectra exhibited nine prominent bands centered at 353, 430, 475, 524, 583, 681, 745, 803, 875 nm corresponding to the transitions from the ground state to 4D3/2, 2P1/2, 2G9/2, 4G7/2, 4G5/2, 4F9/2, 4F7/2, 4F5/2, 4F3/2 excited states, respectively. Moreover, the emission spectra at 355 nm excitation displayed three peaks centered at 903 nm (4F3/2?4I9/2), 1059 nm (4F3/2?4I11/2) and 1333 nm (4F3/2?4I13/2), respectively. Fluorescence lifetime was recorded between 53.69 to 28.43 µs. It was found that varying concentration of Nd3+ ions strongly affected the physical, structural and optical properties of the glass samples

Effect of composition deviation on the microstructure and luminescence properties of Nd:YAG ceramics

Neodymium-doped yttrium aluminum garnet (Nd:YAG) ceramics with different Al2O3/Y2O3 deviation levels were prepared using a solid-state reaction-vacuum sintering method. Transparent ceramics were obtained with their composition in between stoichiometric Nd: YAG Y2.97Nd0.03Al5O12 and 2% Y2O3 excess Nd: YAG Y2.97Nd0.03Al5O12.2%Y2O3. The stoichiometric Nd: YAG ceramic obtains a homogeneous grain microstructure and clean grain boundaries. Non-stoichiometric compositions lead to ceramic microstructures different from that of the stoichiometric Nd: YAG. Nanograins of excess Al2O3 remain inside the Nd: YAG grains in Al2O3-excess ceramics, while Y-rich compounds recrystallize at the Nd: YAG grain boundaries in Y2O3-excess ceramics. Photoluminescence spectra of the sintered ceramics around 808 and 1064 nm were also studied. Peak positions of their luminescence spectra are little affected by composition deviation, while their intensity evidently declines due to the existence of a second phase arising from the composition deviation. The results of this work can contribute toward the controllable synthesis of highly transparent YAG ceramics and further exploration of the Nd ion spectra

Influence of Wurtzite ZnO Morphology on Piezophototronic Effect in Photocatalysis

A piezoelectric field promotes the photocatalytic activity of a photocatalyst by helping separating photo-generated charge carriers. Wurtzite phase ZnO is a typical photocatalyst with a piezoelectric property, thus self-assisted photocatalysis with ZnO based on the piezophototronic effect can be achieved. ZnO nanorods or nanowires with a clear c-axis have been well studied, while other morphologies have not been fully discussed. In this work, we prepared wurtzite phase ZnO with four different morphologies. By comparing their photocatalytic activity for degradation of Rhodamine B under the same mechanical energy source provided by ultrasound, the effect of morphology and exposed facets on photo-induced charge separation were highlighted. The ZnO nanowire photocatalyst delivered an impressive improvement in photocatalytic efficiency when ultrasound driven, suggesting that the morphology-related piezophototronic effect had a positive effect on separation of photo-generated charge carriers, and more exposed active facets benefitted the utilization of charge carriers

TiO₂@Carbon Photocatalysts: The Effect of Carbon Thickness on Catalysis

Nanocomposites composed of TiO₂ and carbon materials (C) are widely popular photocatalysts because they combine the advantages of TiO₂ (good UV photocatalytic activity, low cost, and stability) to the enhanced charge carrier separation and lower charge transfer resistance brought by carbon. However, the presence of carbon can also be detrimental to the photocatalytic performance as it can block the passage of light and prevent the reactant from accessing the TiO₂ surface. Here using a novel interfacial in situ polymer encapsulation–graphitization method, where a glucose-containing polymer was grown directly on the surface of the TiO₂, we have prepared uniform TiO₂@C core–shell structures. The thickness of the carbon shell can be precisely and easily tuned between 0.5 and 8 nm by simply programming the polymer growth on TiO₂. The resulting core@shell TiO₂@C nanostructures are not black and they possess the highest activity for the photodegradation of organic compounds when the carbon shell thickness is 1–2 nm, corresponding to ∼3–5 graphene layers. Photoluminescence and photocurrent generation tests further confirm the crucial contribution of the carbon shell on charge carrier separation and transport. This in situ polymeric encapsulation approach allows for the careful tuning of the thickness of graphite-like carbon, and it potentially constitutes a general and efficient route to prepare other oxide@C catalysts, which can therefore largely expand the applications of nanomaterials in catalysis

Fluorescent graphene quantum dots as traceable, pH-sensitive drug delivery systems

Graphene quantum dots (GQDs) were rationally fabricated as a traceable drug delivery system for the targeted, pH-sensitive delivery of a chemotherapeutic drug into cancer cells. The GQDs served as fluorescent carriers for a well-known anticancer drug, doxorubicin (Dox). The whole system has the capacity for simultaneous tracking of the carrier and of drug release. Dox release is triggered upon acidification of the intracellular vesicles, where the carriers are located after their uptake by cancer cells. Further functionalization of the loaded carriers with targeting moieties such as arginine-glycine-aspartic acid (RGD) peptides enhanced their uptake by cancer cells. DU-145 and PC-3 human prostate cancer cell lines were used to evaluate the anticancer ability of Dox-loaded RGD-modified GQDs (Dox-RGD-GQDs). The results demonstrated the feasibility of using GQDs as traceable drug delivery systems with the ability for the pH-triggered delivery of drugs into target cells

Ultrasmall Fe3O4 nanoparticles self-assembly induced dual-mode T1/T2-weighted magnetic resonance imaging and enhanced tumor synergetic theranostics

Abstract Individual theranostic agents with dual-mode MRI responses and therapeutic efficacy have attracted extensive interest due to the real-time monitor and high effective treatment, which endow the providential treatment and avoid the repeated medication with side effects. However, it is difficult to achieve the integrated strategy of MRI and therapeutic drug due to complicated synthesis route, low efficiency and potential biosafety issues. In this study, novel self-assembled ultrasmall Fe3O4 nanoclusters were developed for tumor-targeted dual-mode T1/T2-weighted magnetic resonance imaging (MRI) guided synergetic chemodynamic therapy (CDT) and chemotherapy. The self-assembled ultrasmall Fe3O4 nanoclusters synthesized by facilely modifying ultrasmall Fe3O4 nanoparticles with 2,3-dimercaptosuccinic acid (DMSA) molecule possess long-term stability and mass production ability. The proposed ultrasmall Fe3O4 nanoclusters shows excellent dual-mode T1 and T2 MRI capacities as well as favorable CDT ability due to the appropriate size effect and the abundant Fe ion on the surface of ultrasmall Fe3O4 nanoclusters. After conjugation with the tumor targeting ligand Arg-Gly-Asp (RGD) and chemotherapy drug doxorubicin (Dox), the functionalized Fe3O4 nanoclusters achieve enhanced tumor accumulation and retention effects and synergetic CDT and chemotherapy function, which serve as a powerful integrated theranostic platform for cancer treatment

Mesoporous Silica Promotes Osteogenesis of Human Adipose-Derived Stem Cells Identified by a High-Throughput Microfluidic Chip Assay

Silicon-derived biomaterials are conducive to regulating the fate of osteo-related stem cells, while their effects on the osteogenic differentiation of human adipose-derived stem cells (hADSCs) remain inconclusive. Mesoporous silica (mSiO2) is synthesized in a facile route that exhibited the capability of promoting osteogenic differentiation of hADSCs. The metabolism of SiO2 in cells is proposed according to the colocalization fluorescence analysis between lysosomes and nanoparticles. The released silicon elements promote osteogenic differentiation. The detection of secretory proteins through numerous parallel experiments performed via a microfluidic chip confirms the positive effect of SiO2 on the osteogenic differentiation of hADSCs. Moreover, constructed with superparamagnetic iron oxide (Fe3O4), the magnetic nanoparticles (MNPs) of Fe3O4@mSiO2 endow the cells with magnetic resonance imaging (MRI) properties. The MNP-regulated osteogenic differentiation of autologous adipose-derived stem cells provides considerable clinical application prospects for stem cell therapy of bone tissue repair with an effective reduction in immune rejection