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Single-atom based photocatalysts have been widely used in the degradation of organic pollutants due to their excellent activity, nearly 100 % atomic utilization efficiency and well-defined active centers. Here, we propose a single Co atom cocatalyst coordinated by nitrogen-doped graphene (Co-NG) to enhance the photocatalytic activity of perylene diimide (PDI) toward bisphenol A (BPA) degradation. Firstly, the self-assembled PDI on the surface of Co-NG exhibits a uniform dispersion state, which facilitates electron transport across the interface. Secondly, Nitrogen-doped graphene can act as a charge transfer bridge to facilitate charge migration from PDI to single Co atom catalytic center. Therefore, in the photocatalytic degradation of BPA, the Co-NG/PDI composite photocatalyst showed a significant increase in activity. 7 % Co-NG/PDI composite possesses the best photocatalytic performance, and the apparent rate is 6.64 times and 7.6 times higher than those of self-assembled PDI and Co-NG. The excellent activity is due to its high photogenerated carrier migration and transfer efficiency. Furthermore, the results of free radical capture experiment and ESR test confirm that singlet oxygen, superoxide radical, hydroxyl radical and hole are the main active species in the degradation process of BPA. We detected the intermediate products and proposed the degradation by LC-MS analysis. This study may provide a promising sunlight-driven photocatalyst for the treatment of the BPA in wastewater. [Display omitted] • The spatial stereo structure PDI was synthesized and the migration distance of optical carriers was shortened effectively. • Co-NG/PDI was synthesized by anchoring Co single atom of cobalt on nitrogen-doped graphene as a cocatalyst for PDI. • The Co-NG/PDI compositehas better visible light photocatalytic degradation BPA activity than self-assembled PDI. [ABSTRACT FROM AUTHOR]

To obtain spherical MoNbTaWZr powders, porous agglomerated MoNbTaWZr particles prepared by spray granulation were subsequently processed by plasma spheroidization. The microstructure, morphology, particle size distribution, purity and property of each step during process were systematically investigated. Results show that the obtained spherical MoNbTaWZr powder has dense structure, smooth surface, and good sphericity in shape. It also has narrow particle size distribution, while D 10 , D 50 , D 90 and D av were 32.0 µm, 42.3 µm, 56.0 µm and 43.2 µm, respectively. The powder has a high purity, and the concentration of oxygen, hydrogen, carbon, and nitrogen were all at ppm. In addition, excellent flowability (8.89 s/50 g) and apparent density (7.27 g/cm3) are benefit from high spheroidization ratio (98.4 %) and dense structure. The spherical powder also exhibits a high nano-hardness due to solid solution strengthening and refinement in dendritic structures. ● Spherical MoNbTaWZr powder was successfully prepared by spray granulation combined with plasma spheroidization. ● Morphology, microstructure, particle size, and purity during preparation were systematic investigated. ● The obtained powder has narrow size distribution, high purity, and good flowability. ● High purity benefits from deoxidation during spheroidization process. [ABSTRACT FROM AUTHOR]

Stretchable supercapacitors with simultaneously high energy/power densities and long life can enrich integrated power options for ever-increasing wearable electronics. However, supercapacitors with high electrochemical performances while maintaining high stretchability are still challenging. Herein, we report stretchable sodium ion capacitors (S-SICs) based on multi-dimensionally and hierarchically elastomeric composite electrodes, and stretchable high voltage gel polymer electrolyte (3.0 V). The elastomeric composite electrode is constructed by stretchable 3D electrospun polyurethane (PU) fibrous mat and conductive 1D Ag nanowire network. 2D MoSe 2 /MXene and 3D AC/MXene as anodic and cathodic materials are embedded in this conductive and stretchable mat. This hierarchical structure enables multi-dimensional conductive connections under tensile condition. The pre-strain treatment on PU fibrous mat further increases the relatively stretching distance before losing conductive connection among hierarchical components. The electrodes exhibit superior sodium ion storage performances (420 mAh g−1 at 5 A g−1), as well as good stretchability and stability (95% after 1000 cycles at 2 A g−1). Based on this, the S-SICs with high operating voltage demonstrate high energy/power densities (max. 5.44 mWh cm−3, 493.55 mW cm−3) and good stretchability. This prototypical exhibition of S-SICs indicates a promising design direction of stretchable supercapacitors with high electrochemical performances and tolerance of stretchability. • Stretchable sodium ion capacitors (S-SICs) are promising. • Multi-dimensionally and hierarchically composite enable superior electrodes. • Pre-strain increases tolerances of stretchability and electrochemical activity. • S-SICs demonstrate high energy/power densities and good stretchability. [ABSTRACT FROM AUTHOR]

Photocatalytic nitrogen (N 2) fixation provides a green avenue for the production of ammonia (NH 3), which is extremely significant for global biogeochemical cycle. However, there is still lack of highly efficient catalyst to improve the N 2 photofixation efficiency. In this work, oxygen vacancy engineered perovskite SrTiO 3 materials have been prepared by post reduction using lithium alkylamine solution and served as effective catalysts for visible-light-driven N 2 -to-NH 3 conversion. The formation and concentration of oxygen vacancies were confirmed by electron paramagnetic resonance, X-ray photoelectron spectroscopy and thermogravimetric analyses. The SrTiO 3 catalyst with optimized oxygen vacancies concentration exhibited improved photocatalytic N 2 reduction rate of 306.87 μmol·g−1·h−1, which is approach ten-fold higher than that of pristine SrTiO 3. Electrochemical impedance spectroscopy and photoluminescence measurements reveal that optimum amount of oxygen vacancies can promote the effective adsorption of N 2 molecules and improve the photocatalytic performance by facilitating the fast separation of photo-generated charge carriers. Moreover, the as-fabricated defective SrTiO 3 exhibited outstanding stability, which makes it emerge the promising potential for further practical applications. This work offers a feasible method for the design of high performance photocatalysts through defect engineering. • Synthesized defective SrTiO 3 catalysts by lithium alkylamine solution reduction. • Oxygen vacancies regulation to improve the photocatalytic NRR activity for SrTiO 3. • About ten-fold NH 3 formation rate (873.48 μmol·g−1·h−1) to original SrTiO 3. • Defective SrTiO 3 suppressed the recombination of the photogenerated carriers. [ABSTRACT FROM AUTHOR]

• The (Fe x , Co y)-NG/mpg-C 3 N 4 materials exhibited excellent activity due to the synergistic effect of well-defined dual sites. The photocatalytic hydrogen evolution reaction is a promising and powerful approach to replace traditional fossil fuels. Herein, we have fabricated Fe, Co dual single atoms dispersed on nitrogen-doped graphene ((Fe x , Co y)-NG) by freeze-drying method, which can as a highly efficient co-catalyst. The (Fe x , Co y)-NG loaded mesoporous graphitic carbon nitride (mpg-C 3 N 4) exhibits an excellently high performance for photocatalytic hydrogen evolution. The high activity can belong to two ways: (i) the ultrathin mpg-C 3 N 4 not only increases the absorption and active sites but also shortens the charge migration distance; (ii) The nitrogen functional groups from NG can provide abundant coordination sites to evenly bind Fe and Co atoms. The photocatalytic hydrogen evolution performances (Fe x , Co y)-NG co-catalyst with different content ratios of Fe atoms and Co atoms were also investigated. The optimized hydrogen production rate (1958 μmol g−1) of 5 wt% (Fe 0.2 , Co 0.8)-NG/mpg-C 3 N 4 is obviously higher compared to the monometallic counterparts (5 wt% Fe-NG/mpg-C 3 N 4 or 5 wt% Co-NG/mpg-C 3 N 4). The higher photoactivities are due to the synergistic effect between Fe and Co. [ABSTRACT FROM AUTHOR]