Graphitic carbon nitride (g-CN) behaving as a layered feature with graphite was indexed as a high-content nitrogen-doping carbon material, attracting increasing attention for application in energy storage devices. However, poor conductivity and resulting serious irreversible capacity loss were pronounced for g-CN material due to its high nitrogen content. In this work, magnesiothermic denitriding technology is demonstrated to reduce the nitrogen content of g-CN (especially graphitic nitrogen) for enhanced lithium storage properties as lithium ion battery anodes. The obtained nitrogen-deficient g-CN (ND-g-CN) exhibits a thinner and more porous structure composed of an abundance of relatively low nitrogen doping wrinkled graphene nanosheets. A highly reversible lithium storage capacity of 2753 mAh/g was obtained after the 300th cycle with an enhanced cycling stability and rate capability. The presented nitrogen-deficient g-CN with outstanding electrochemical performances may unambiguously promote the application of g-CN materials in energy-storage devices.

Novel g-CN/CoO nanocomposite application for photocatalytic H evolution were designed and fabricated for the first time in this work. The structure and morphology of g-CN/CoO were investigated by a wide range of characterization methods. The obtained g-CN/CoO composites exhibited more-efficient utilization of solar energy than pure g-CN did, resulting in higher photocatalytic activity for H evolution. The optimum photoactivity in H evolution under visible-light irradiation for g-CN/CoO composites with a CoO mass content of 0.5 wt % (651.3 μmol h g) was up to 3 times as high as that of pure g-CN (220.16 μmol h g). The remarkably increased photocatalytic performance of g-CN/CoO composites was mainly attributed to the synergistic effect of the junction or interface formed between g-CN and CoO.

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The generation of direct white-light emission of the coexisting valence-varied europium-lanthanum aluminate through substitution of cations into the host and its resultant adjustment of the energy transfer have been presented. With respect to La(0.99-x)Sr(x)AlO(3-delta):Eu(0.01) and La(0.994)Al(1-x)O(3-delta):Eu(0.006), and Mn(x), Li(0.012), the green-light emission positioned at 515 nm plays a key role to color mix for white light and can be efficiently tuned by adjusting the transfer of energy and relevant transition emissions between the luminous centers of Eu(2+) and Eu(3+)/Mn(2+), via varying amounts of dopants. Direct white-light emission with optimized values of 86 for the color rendering index and 5091 K for the correlated color temperature has been achieved for lanthanum aluminate by this mixed-valence means.