The oxygen-buffering CeO2 effectively protects the available active sites of the ZIF-67-derived Co3O4@carbon to improve oxygen reduction/evolution reaction activities.

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Driven by decreasing prices for photovoltaic (PV) systems and incentive programs of different governments, almost 100 GW of PV and over 100 GW of wind turbines (WT) have been integrated in the European power system by 2014. In some areas, the electricity generation already exceeds the demand, curtailing generation or pushing the existing power transmission infrastructure to its limits in certain hours. In order to reach the European Commission's targets for 2050, the integration of renewable energies will require flexibility sources, independent of conventional generation, in order to provide standard security of supply. Together different flexibility sources will ensure the match between demand and supply at any given time. Energy storage systems can provide this flexibility by shifting the load temporally while transmission grids provide the shift of load spatially. Up to a certain extent, transmission capacity and storage capacity can replace each other, i.e. storage can reduce the load on transmission infrastructure by mitigating local peaks in load and/or generation. For the transition to a fully renewable energy system by 2050, major changes have to be achieved in the structure of the power system. The planning tool GENESYS is a holistic approach that optimises the allocation and size of different generation technologies, storage systems and transnational transmission corridors of a European power system. The source code for the mentioned tool is available free of charge under LGPL license. It can be freely parameterized by the user which allows the study of different power systems under individual assumptions with regard to load, generation potential and cost of the different system components. This publication will give an introduction to the planning methodology, the system model and the optimisation approach. Optimisation results obtained with GENESYS for a fully renewable electricity system for Europe and a cost structure expected for 2050 will be presented together with sensitivity analyses investigating main assumptions. Outcomes show the optimal allocation of PV and WT in a European power system, the resulting demand for storage capacities of different technologies and the capacity of the overlay grid.

The photoluminescence (PL) emission mechanism of graphitic carbon nitride (g-CN) is still ambiguous and the application of PL g-CN powder as a solid sensing platform has not been explored. Herein we highlight a strategy to prepare g-CN powder with strong green PL by doping phenyl groups in a carbon nitride network. Compared with pristine g-CN, doping of phenyl groups greatly enhances the PL efficiency and Stokes shift. Theoretical calculations based on density function theory indicate that phenyl groups change the electronic structure of the carbon nitride network and have an obvious contribution to the LUMO of phenyl-doped g-CN, which may be the main reason for the enhancement of the PL efficiency and Stokes shift. Taking advantage of the high PL efficiency, large Stokes shift and high photo-stability, phenyl-doped g-CN powder shows promising application for the imaging of latent fingerprints.

The application of fluorescent graphitic carbon nitride (g-C 3 N 4 ) nanomaterials was limited by short photoluminescence (PL) wavelength. It is great desirable to develop g-C 3 N 4 nanomaterials with long PL wavelength and high quantum yield to expand their application. Herein phenyl-modified and sulfur doped g-C 3 N 4 (PhCNS) powders with tunable PL peak from 520 to 630 nm were prepared by copolymerization of 2,4diamino-6-phenyl-1,3,5-triazine and trithiocyanuric acid. The copolymerization process of PhCNS powders was proposed after chemical structure characterization and PL mechanism of PhCNS powders were investigated by transient fluorescence. In virtue of tunable PL color, broad PL peak, and high quantum yield, PhCNS powders were utilized to fabricate green, yellow, and white light-emitting diodes with high color quality and PhCNS nanosheets were applied for multicolor bioimaging. This work provides a pathway for exploring g-C 3 N 4 nanomaterials with long PL wavelength and facilitates their application in biocompatible optoelectronic devices, fluorescent bioimaging.

Hydroxide ion (OH − ) adsorption process is critical for accelerating the half-reactions of both metal−air batteries and direct methanol fuel cells in alkaline media. This study designs a rational catalyst/cocatalyst by constructing the readily available OH − adsorption sites to boost oxygen evolution reaction (OER) and methanol oxidation reaction (MOR). Cobalt selenide-coated nickel selenide nanorods are in situ grown on nickel foam to obtain CoSe/NiSe-nrs/NF via a one-pot solvothermal synthesis route. CoSe-0.2/NiSe-nrs/ NF (Co/Ni molar ratio of 0.26) exhibits an excellent OER activity(an overpotential of 310 mV at 100 mA cm −2 and a Tafel slope of 58.3 mV dec −1 ). The differently oriented CoSe/ NiSe-nrs with a velutipes-like structure and metallic property provide a promising electrical conductivity for charge transfer. In situ X-ray diffraction tests verify the crystallization of active β-NiOOH during OER, and the crystallized NiOOH/CoOOH contributes to the excellent OER cycling stability in alkaline media. Synergistic effects between CoSe and NiSe-nrs/NF can balance the formation of NiOOH/CoOOH heterostructures to govern the exposure of available active sites. NiOOH/CoOOH as a highly active component can energetically adsorb OH − to promote OER. CoSe/NiSe-nrs/NFs as a low Pt-loading (0.5 wt%) support offer the mutually beneficial interactions for promoting cocatalytic and CO ads (poisonous intermediate) co-oxidation activities toward MOR. The electrochemically active surface area and mass activity of Pt/CoSe-0.2/NiSe-nrs/NF are 85 m 2 g pt −1 and 1437.1 mA mg pt −1 , respectively, which are much higher than those of commercial Pt/C (10.0 wt%). OH − absorbed on the NiOOH/CoOOH structure eliminates CO ads on the Pt surface via bifunctional mechanisms to improve the MOR activity. This study provides a promising reference for designing the versatile catalysts for energy conversion.

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