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The synthesis of zeolites from natural aluminosilicate minerals has drawn extensive attention due to its significant utility in greening the zeolite manufacturing process. In this study, pure-phase NaX zeolite was synthesized via a low-temperature hydrothermal method, utilizing natural, low-quality attapulgite clay as the raw material. Acidified clay was fully activated through alkali fusion at 200 °C, and the impact of alkali fusion temperature, H2O/Na2O ratio, aging temperature, and crystallization time on the resulting crystalline NaX zeolite was investigated. The optimal conditions for obtaining pure NaX zeolite were determined to be alkali melting at 200 °C for 4 h, an H2O/Na2O ratio of 50, aging at 40 °C, and a crystallization period of 11 h at 90 °C. With a large BET surface area of 328.43 m2/g, the obtained NaX zeolite was used to adsorb Pb2+ from wastewater with a removal rate of 95%. This research provides a valuable method for the extensive and efficient utilization of low-grade natural attapulgite clay. Moreover, this is the first report on the synthesis of pure-phase NaX zeolite using only low-quality natural attapulgite clay as raw material through an atmospheric pressure water bath method. [ABSTRACT FROM AUTHOR]

In this paper, oil-in-water-in-oil (O/W/O) double Pickering emulsions were prepared by purified and modified attapulgite (ATP), and modified nano-Fe3O4 as stable particles. By using the Pickering emulsion as a template and using methyl methacrylate (MMA), butyl methacrylate ester (BMA) and styrene (St) as monomers, ATP/P(MMA-BMA-St)/Fe3O4 composite porous resins were then prepared. The oil absorption performance of the composites was investigated. The results showed that the composite materials prepared by the double Pickering emulsion template method exhibited a three-dimensional (3D) porous structure. When using the optimal conditions (m MMA: m BMA = 3:2, m (MMA+BMA): m St = 1:2, initiator = 5.33%, crosslinking agent = 20%, modified attapulgite = 0.33% and oil phase/water phase = 1:4), the prepared porous material had the best oil absorption performance, resulting in a diesel oil absorption rate and oil retention rate of 897.29 and 84.76% respectively. This study provides a simple, economic and environmentally friendly method for the preparation of inorganic–organic composite porous materials, which has great application potential in the field of oil treatment. Oil-in-water-in-oil (O/W/O) double Pickering emulsions were prepared using purified and modified attapulgite (ATP) and modified nano-Fe3O4 as stable particles and then used as templates to form ATP/P(MMA-BMA-St)/Fe3O4 composite porous resins. The experiment provides a simple, economic and environmentally friendly method for the preparation of inorganic–organic composite porous materials, which are expected to have great application potential in the field of oil treatment. [ABSTRACT FROM AUTHOR]

The demand for advanced energy storage devices such as supercapacitors and lithium-ion batteries has been increasing to meet the application requirements of hybrid vehicles and renewable energy systems. Here, high energy density aqueous asymmetric supercapacitor (ASC) is assembled based on chestnut shell-based activated carbon (CAC)/PANI composite positive electrode and tungsten trioxide (WO3) nanowires negative electrode. The CAC/PANI composite and WO3 nanowires were synthesized through an interfacial polymerization method and a simple sodium sulfate assisted hydrothermal process, respectively. The CAC/PANI//WO3 ASC device operates with a voltage of 1.5 V in 1 M H2SO4 electrolyte and achieved a high energy density of 15.4 Wh kg−1 at a power density of 252 W kg−1. Furthermore, the device shows an excellent cycling performance with capacitance retention of 83% after 1500 cycles. [ABSTRACT FROM AUTHOR]

The reaction mechanism of the gas-phase PtCH with HS has been systematically investigated on the doublet and quartet potential energy surfaces at BPW91/6-311++ G(2 d, p)∪ SDD level. The Pt in PtCH prefers to attack S-H bond in HS. For PtCH + HS reaction, the potential energy surfaces (PESs), including three reaction pathways of hydrogen (including one and two hydrogen elimination) and methane elimination, have been explored and characterized. By contrast with hydrogen elimination, methane elimination reaction channel is energetically favorable, which is in good agreement with the experimental observation. The optimal S-H bond activation is the first step, followed by cleavage of Pt-C and Pt-S bond. About the path a and b, the lowering of activation barrier is mainly caused by the more stabilizing transition state interaction $$\varDelta E_{\text{int}}^{ \ne }$$ , which is the actual interaction energy between the deformed reactants in the transition state. [ABSTRACT FROM AUTHOR]

Gas-phase H2 activation by PtO+ and ${\rm PtO}_{2}^{+}$ were studied at the density functional level of theory (DFT) using the relativistic effective core potential (RECP) of Stuttgart basis sets on platinum atom and UB3LYP/6-311+G(2d,2p) level on hydrogen and oxygen atoms. Two reaction profiles corresponding to the doublet and quartet multiplicities were investigated in order to ascertain the presence of some spin inversion during the H2 reduction. The electron-transfer reactivity of the reactions were analyzed using the two-state model, and the strongly crossing behavior on the transition state (TS) area were shown. Finally, the actions of frontier molecular orbitals in minimum-energy crossing point (MECP) have been illuminated briefly. These theoretical results can act as a guide to further theoretical and experimental research. H2 activation mediated by metal oxide cations were found to be an exothermic spin-forbidden process resulting from a crossing between quartet and doublet profiles. To evaluate the spin-forbidden process in the reaction pathway, the spin-obit coupling (SOC) matrix elements are calculated at the MECP with the different potential energy surfaces (PESs) and the probability of crossing between the adiabatic potential-energy surfaces during a single pass through the avoided crossing region was described. Therefore, the intersystem crossing (ISC) at crossing points (CP) occur efficiently because of the large SOC (ca. 85.58 cm-1) involved. [ABSTRACT FROM AUTHOR]

Fe3+-doped TiO2 composite nanoparticles with different doping amounts were successfully synthesized using sol-gel method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultravioletvisible spectroscopy (UV-Vis) diffuse reflectance spectra (DRS). The photocatalytic degradation of methylene blue was used as a model reaction to evaluate the photocatalytic activity of Fe3+/TiO2 nanoparticles under visible light irradiation. The influence of doping amount of Fe3+ ( ω: 0.00%–3.00%) on photocatalytic activities of TiO2 was investigated. Results show that the size of Fe3+/TiO2 particles decreases with the increase of the amount of Fe3+ and their absorption spectra are broaden and absorption intensities are also increased. Doping Fe3+ can control the conversion of TiO2 from anatase to rutile. The doping amount of Fe3+ remarkably affects the activity of the catalyst, and the optimum efficiency occurs at about the doping amount of 0.3%. The appropriate doping of Fe3+ can markedly increase the catalytic activity of TiO2 under visible light irradiation. [ABSTRACT FROM AUTHOR]

Fibrillar conductive polyaniline/TiO2 (PANI/TiO2) nanocomposites with different TiO2 amount were synthesized with a template-free in situ polymerization method and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and conductivity measurement. The morphology determination shows that the PANI/TiO2 composite nanofibers are relatively uniform with the diameter and length in the range of 20–40 nm and 390–420 nm respectively. It also shows that the TiO2 of the composite is rutile crystalline and PANI has some degree of crystallinity. The IR measurement indicates that there is a strong interaction between the PANI and TiO2 nanoparticles, and it has a beneficial effect on the thermal stability of the composite nanofiber. The conductivity of PANI/TiO2 composites changes with TiO2 amount and reaches an optimum value of 2.86 S/cm at 11.1 wt% TiO2. [ABSTRACT FROM AUTHOR]