High-efficiency visible-light-driven oxidation of primary C-H bonds in toluene over a CsPbBr3 perovskite supported by hierarchical TiO2 nanoflakes.

Photocatalytic oxidation of toluene to valuable fine chemicals is of great significance, yet faces challenges in the development of advanced catalysts with both high activity and selectivity for the activation of inert C(sp3)-H bonds. Halide perovskites with remarkable optoelectronic properties have shown to be prospective photoactive materials, but the bulky structure with a small surface area and severe recombination of photogenerated electron-hole pairs are obstacles to application. Here, we fabricate a hierarchical nanoflower-shaped CsPbBr3/TiO2 heterojunction by assembling CsPbBr3 nanoparticles on 2D TiO2 nanoflake subunits. The design significantly downsizes the size of CsPbBr3 from micrometers to nanometers, and forms a type II heterojunction with intimate interfacial contact between CsPbBr3 and TiO2 nanoflakes, thereby accelerating the separation and transfer of photogenerated charges. Moreover, the formed hierarchical heterojunction increaseslight absorption by refraction and scattering, offers a large surface area and enhances the adsorption of toluene molecules. Consequently, the optimized CsPbBr3/TiO2 exhibits a high performance (10 200 µmol g-1 h-1) for photocatalytic toluene oxidation with high selectivity (85%) for benzaldehyde generation under visible light. The photoactivity is about 20 times higher than that of blank CsPbBr3, and is among the best photocatalytic performances reported for selective oxidation of toluene under visible light irradiation.

Visible-Light-Driven Photocatalytic Dehydrogenation of Alcohols on TiO2 via Ligand-to-Metal Charge Transfer for Coproduction of H2 and Aldehydes.

Developing visible-light-driven photocatalysts for the catalytic dehydrogenation of organics is of great significance for sustainable solar energy utilization. Here, we first report that aromatic alcohols could be efficiently split into H2 and aldehydes over TiO2 under visible-light irradiation through a ligand-to-metal charge transfer (LMCT) mechanism. A series of TiO2 catalysts with different surface contents of the hydroxyl group (-OH) have been synthesized by controlling the hydrothermal and calcination synthesis methods. An optimal H2 production rate of 18.6 µmol h-1 is obtained on TiO2 synthesized from the hydrothermal method with a high content of surface -OH. Experimental characterizations and comparison studies reveal that the surface -OH markedly influences the formation of LMCT complexes and thus changes the visible-light-driven photocatalytic performance. This work is anticipated to inspire further research endeavors in the design and fabrication of visible-light-driven photocatalyst systems based on the LMCT mechanism to realize the simultaneous synthesis of clean fuel and fine chemicals.

Recovery of copper from electroplating sludge using integrated bipolar membrane electrodialysis and electrodeposition.

Electroplating sludge, though a hazardous waste, is a valuable resource as it contains a large amount of precious metals. In this study, copper was recovered from the electroplating sludge using a technology that integrates bipolar membrane electrodialysis (BMED) and electrodeposition. The experimental results showed that Cu2+ in the electroplating sludge was successfully separated and concentrated in the BMED system without adding any chemical reagents; the concentrated Cu2+ was recovered in the form of copper foil in an electrodeposition system. Current density clearly affected the Cu2+ separation and concentration in the BMED system; the current density, solution pH and Cu2+ concentration drastically affected the Cu2+ electrodeposition ratio and the morphology and purity of the obtained copper foil. Under the optimised experimental conditions, 96.4% of Cu2+ was removed from the electroplating sludge and 65.4% of Cu2+ was recovered in the foil form. On increasing the number of electroplating sludge compartments from one to two and three, the current efficiency for recovering Cu2+ increased from 17.4% to 28.5% and 35.2%, respectively, and the specific energy consumption decreased from 11.3 to 6.7 and 5.3 kW h/kg of copper, respectively. The purity of the copper foil was higher than 99.5%. Thus, the integrated technology can be regarded as an effective method for recovering copper from electroplating sludge.

Pt-Chitosan-TiO2 for Efficient Photocatalytic Hydrogen Evolution via Ligand-to-Metal Charge Transfer Mechanism under Visible Light.

The Pt-chitosan-TiO2 charge transfer (CT) complex was synthesized via the sol-gel and impregnation method. The synthesized photocatalysts were thoroughly characterized, and their photocatalytic activity were evaluated toward H2 production through water reduction under visible-light irradiation. The effect of the preparation conditions of the photocatalysts (the degree of deacetylation of chitosan, addition amount of chitosan, and calcination temperature) on the photocatalytic activity was discussed. The optimal Pt-10%DD75-T200 showed a H2 generation rate of 280.4 µmol within 3 h. The remarkable visible-light photocatalytic activity of Pt-chitosan-TiO2 was due to the CT complex formation between chitosan and TiO2, which extended the visible-light absorption and induced the ligand-to-metal charge transfer (LMCT). The photocatalytic mechanism of Pt-chitosan-TiO2 was also investigated. This paper outlines a new and facile pathway for designing novel visible-light-driven photocatalysts that are based on TiO2 modified by polysaccharide biomass wastes that are widely found in nature.

Ultrathin Two-Dimensional ZnIn2S4/Nix-B Heterostructure for High-Performance Photocatalytic Fine Chemical Synthesis and H2 Generation.

Photocatalytic H2 evolution coupled with organic transformation provides a new avenue to cooperatively produce clean fuels and fine chemicals, enabling a more efficient conversion of solar energy. Here, a novel two-dimensional (2D) heterostructure of ultrathin ZnIn2S4 nanosheets decorated with amorphous nickel boride (Nix-B) is prepared for simultaneous photocatalytic anaerobic H2 generation and aromatic aldehydes production. This ZnIn2S4/Nix-B catalyst elaborately combines the ultrathin structure advantage of the ZnIn2S4 semiconductor and the cocatalytic function of Nix-B. A high H2 production rate of 8.9 mmol h-1 g-1 is delivered over the optimal ZnIn2S4/Nix-B with a stoichiometric production of benzaldehyde, which is about 22 times higher than ZnIn2S4. Especially, the H2 evolution rate is much higher than the value (2.8 mmol h-1 g-1) of the traditional photocatalytic half reaction of H2 production with triethanolamine as a sacrificial agent. The apparent quantum yield reaches 24% at 420 nm, representing an advanced photocatalyst system. Moreover, compared with traditional sulfide, hydroxide, and even noble metal modified ZnIn2S4/M counterparts (M = NiS, Ni(OH)2, Pt), the ZnIn2S4/Nix-B also maintains markedly higher photocatalytic activity, showing a highly efficient and economical advantage of the Nix-B cocatalyst. This work sheds light on the exploration of 2D ultrathin semiconductors decorated with novel transition metal boride cocatalyst for efficient photocatalytic organic transformation integrated with solar fuel production.

Construction of TiO2-Eggshell for Efficient Degradation of Tetracycline Hydrochloride: Sunlight Induced In-Situ Formation of Carbonate Radical.

Photocatalytic degradation of an antibiotic by utilizing inexhaustible solar energy represents an ideal solution for tackling global environment issues. The target generation of active oxidative species is highly desirable for the photocatalytic pollutants degradation. Herein, aiming at the molecular structure of tetracycline hydrochloride (TC), we construct sunlight-activated high-efficient catalysts of TiO2-eggshell (TE). The composite ingeniously utilizes the photoactive function of TiO2 and the composition of eggshell, which can produce oxidative ·CO3- species that are especially active for the degradation of aromatic compounds containing phenol or aniline structures. Through the synergistic oxidation of the··CO3- with the traditional holes (h+), superoxide radicals (·O2-) and hydroxyl radicals (·OH) involved in the photocatalytic process, the optimal TE photocatalyst degrades 92.0% TC in 30 min under solar light, which is higher than TiO2 and eggshell. The photocatalytic degradation pathway of TC over TE has been proposed. The response surface methodology is processed by varying four independent parameters (TC concentration, pH, catalyst dosage and reaction time) on a Box-Behnken design (BBD) to optimize the experimental conditions. It is anticipated that the present work can facilitate the development of novel photocatalysts for selective oxidation based on ·CO3-.

Amorphous Boron Dispersed in LaCoO3 with Large Oxygen Vacancies for Efficient Catalytic Propane Oxidation.

Unsatisfactory oxygen mobility is a considerable barrier to the development of perovskites for low-temperature volatile organic compounds (VOCs) oxidation. This work introduced small amounts of dispersed non-metal boron into the LaCoO3 crystal through an easy sol-gel method to create more oxygen defects, which are conducive to the catalytic performance of propane (C3 H8 ) oxidation. It reveals that moderate addition of boron successfully induces a high distortion of the LaCoO3 crystal, decreases the perovskite particle size, and produces a large proportion of bulk Co2+ species corresponding to abundant oxygen vacancies. Additionally, surface Co3+ species, as the acid sites, which are active for cleaving the C-H bonds of C3 H8 molecules, are enriched. As a result, the LCB-7 (molar ratio of Co/B=0.93:0.07) displays the best C3 H8 oxidation activity. Simultaneously, the above catalyst exhibits superior thermal stability against CO2 and H2 O, lasting 200 h. This work provides a new strategy for modifying the catalytic VOCs oxidation performance of perovskites by the regulation of amorphous boron dispersion.

A ZnO@ABS/TPU/CaSiO3 3D skeleton and its adsorption/photocatalysis properties for dye contaminant removal.

Both adsorption and photocatalysis are considered to be effective methods for removing organic contaminants from dye wastewater. In this study, the construction of 3D skeletons based on the nanoparticles ZnO and ABS/TPU/calcium silicate (CaSiO3) (shortened as ATC) were fabricated via fused deposition molding (FDM) technology. Characterization by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) depicted that ZnO nanospheres had been successfully grown on the 3D skeleton surface with an enlarged specific surface area. As the results of the RhB adsorption and photocatalytic degradation experiments showed, the removal ratio of RhB onto the ZnO-ATC skeleton was as high as 97.94% and the synergistic effect of adsorption and photocatalysis greatly shortened the RhB degradation time under ultraviolet light irradiation. The nanocomposites synthesized in this study showed a significant removal ability for organic pollutants, and could effectively overcome the limitation of the secondary removal of photocatalysts.

Rational design of few-layer MoSe2 confined within ZnSe-C hollow porous spheres for high-performance lithium-ion and sodium-ion batteries.

Rechargeable battery systems, including Li-ion batteries and Na-ion batteries, have attracted great interest in energy storage because of their high energy density, low cost, efficient energy storage and suitable redox potential. Nevertheless, their rapid development is still greatly hampered by some typical constraints including low coulombic efficiency, large volume changes and severe particle agglomeration and pulverization during the charge-discharge process. Here, we fabricate a few-layer MoSe2 confined within a ZnSe-C hollow porous sphere nanocomposite through a simple self-assembly strategy followed by selenization, which efficiently circumvents these problems. The fabricated ZnSe/MoSe2@C electrode demonstrates diverse advantages, including the existence of a few-layer structure, an in situ porous carbon matrix, multicomponent coordination and excellent pseudocapacitive behavior. When used as an anode material, it displays extraordinarily attractive electrochemical performance for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). The reversible capacity of ZnSe/MoSe2@C for LIBs reaches as high as 1051 mA h g-1 at 0.2 A g-1 (150 cycles). A long-term high-rate cycling test reveals an excellent stability of 524 mA h g-1 at 4 A g-1 after 600 cycles. In addition, for SIBs, ZnSe/MoSe2@C also manifests a high initial coulombic efficiency of 89% at 0.2 A g-1 and a remarkable reversible capacity of 381 mA h g-1 at a high current density of 4 A g-1 even after 250 cycles with negligible capacity loss. This is one of the best performances of ZnSe-based anode materials for SIBs reported so far. The regulation strategy reported in the present work is expected to offer new insights into the fabrication of high performance anode materials for SIBs.

Facile synthesis of hierarchical lychee-like Zn3V3O8@C/rGO nanospheres as high-performance anodes for lithium ion batteries.

In the present work, the hierarchical Zn3V3O8@C/rGO composite with a unique lychee-like architecture was fabricated by a simple one-pot ethanol thermal reduction strategy. When used as an anode material, it exhibited outstanding electrochemical performance for lithium-ion batteries (LIBs). For instance, the Zn3V3O8@C/rGO composite delivers high reversible capacities (1012 mAh g-1 at 0.1 A g-1 after 200 cycles) and high rate stability (448 mAh g-1 at 4 A g-1 after 1000 cycles). This outstanding performance can be attributed to the synergistic effect of the diverse structural virtues, effective interface and dual-spatially hybrid carbon network. Significantly, this one-pot simple strategy can be extended to fabricating highly stable and high rate performance of vanadates or other anode materials for LIBs.

S-Doped Sb2O3 Nanocrystal: an Efficient Visible-Light Catalyst for Organic Degradation.

The S-doped Sb2O3 nanocrystals were successfully synthesized using SbCl3 and thioacetamide (TAA) as precursors via a facile one-step hydrothermal method. The effects of pH of the precursor reaction solution on the product composition and property were determined. The results indicated that the doping amount of S could be tuned by adjusting the pH of the precursor solution. Furthermore, the S entered into the interstitial site of Sb2O3 crystals as S2-, which broadened the absorption wavelength range of the Sb2O3 nanocrystal. The S-doped Sb2O3 exhibited an excellent visible-light-driven photocatalytic activity in the decomposition of methyl orange and 4-phenylazophenol. Last, a possible photocatalytic mechanism of the S-doped Sb2O3 under visible light irradiation was proposed.

Visible light-assisted efficient degradation of dye pollutants with biomass-supported TiO2 hybrids.

The objective of this work was to develop a novel organic-inorganic hybrid nanomaterial from agricultural biomass waste for environmental applications. The sugarcane bagasse (SB) supported TiO2 hybrids were firstly synthesized via a sol-gel method. A series of characterizations were carried out to reveal the structures and components of obtained hybrids. Due to organic-inorganic hybrid (OIH) effect and element doping, the SB-TiO2 hybrid can expand its optical absorbance ranging from ultraviolet to visible light. The optimal hybrid catalyst prepared with SB doping amount of 2g in 100mL titanic gel and calcined at 200°C was able to degradate 95.0% methyl orange (MO) in 5h under visible light. This study will pave a new and facile pathway for novel visible light driven photocatalysts based on TiO2 modified by agricultural biomass waste.

Prefabricated partial distal urethral in 2-staged repair of proximal hypospadias with severe chordee.

PURPOSE: To describe a new technique for staged hypospadias repair in which the urethral plate is divided and tubularized transverse island flap prefabricated partial distal urethral at the time of the first stage. MATERIALS AND METHODS: Sixteen patients with proximal hypospadias associated with severe chordee were operated on using a new staged technique. At the time of the first stage, the urethral plate was divided and chordee was corrected. Then tubularized transverse island flap was used to prefabricate partial distal urethra. The defective urethra was repaired using the Thiersch-Duplay principle at the second stage. RESULTS: All participants have completed both stages of the operation. The mean follow-up duration was 18.4 months (range from 6 to 72 months). In the first-stage surgery, the modified tabularized transverse preputial island flap was performed on 6 patients, whereas the modified preputial double-faced island flap was performed on the other 10 patients. All of the prefabricated partial distal neourethras had no evidence of stenosis or scarring. The result of the second-stage procedure was a complete penis with integrated urethral. All patients were satisfied with cosmetic and functional results. Neither stricture nor diverticula was observed. A good urinary stream during the urination was attained in 12 (75.0%) patients. Four cases (25.0%) developed urethrocutaneous fistula after the second stage repair. CONCLUSIONS: In our preliminary series, this procedure improved functional and cosmetic results. It may be applicable to most cases of proximal hypospadias. Even when complications occur, they are less severe compared to those of the traditional staged approach.

Preparation and characterization of electrospun La(1-x)Ce(x)CoO(δ): Application to catalytic oxidation of benzene.

An electrospinning with calcination process was employed for the synthesis of La1-xCexCoOδ (x=0, 0.2, 0.4, 0.6, 0.8, and 1.0) oxides. These catalysts were investigated in terms of total benzene oxidation, and characterized by means of XRD, BET, H2-TPR, SEM, XPS, and TEM techniques. The results show that the amount of Ce doping obviously affects the physicochemical and catalytic properties of La1-xCexCoOδ, and when x=1.0, CeCoOδ exhibits the best activity and highly thermal durability for catalytic oxidation of benzene. Additionally, it is demonstrated that the increased activity over perovskite phase dominated oxides is ascribed to a larger surface area while the activity enhancement over metal oxides mainly results from a higher valance of Co and better redox property.