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.

The modulation of TiO 2 structure can effectively alter the oxidation kinetics and pathway of sacrificial ethanol during the water-splitting reaction and dramatically adjust the selectivity of the valuable coupling product 2,3-butanediol from 0.0% to 96.6%, showing the possibility of photohydrogen production in green and economical indexes.Light-driven water splitting to produce hydrogen has drawn great attention due to increasing global concerns on fossil energy resources and climate problems. 1,2 Since the electrochemical photolysis of water on a titanium oxide (TiO 2 ) electrode was first discovered by Fujishima and Honda, 3 great progress has been achieved in understanding the microscopic processes involved in the photochemical systems 4-6 and catalysts, 7-10 and in the modulation of catalyst structures for visible light harvesting. 11-13 However, light-driven hydrogen production still faces many challenging issues for practical application.Light-driven water splitting intrinsically undergoes two reaction moieties: the reduction of protons (H + ) to molecular hydrogen by photo-excited electrons, and the oxidation of water to dioxygen by holes. 14 In an ideal photocatalytic system for permanent high-rate hydrogen generation, the oxidation half-reaction should match well with the reduction half-reaction; however, in most cases, it proceeds at a considerably low rate and greatly limits the total photocatalytic oxidation-reduction cycle. Sacrificial reductants, such as methanol and ethanol, are normally required to speed up hole consumption and slow down electron-hole recombination, 15,16 which can dramatically enhance hydrogen evolution by several orders of magnitude. 17 However, the use of sacrificial reductants undesirably brings along several problems, such as: (1) the water-splitting reaction is actually changed into a redox reaction between water and the sacrificial reductants, greatly increasing the system cost; and (2) sacrificial alcohols are normally converted to CO 2 and other oxidation products, 18,19 causing the photocatalytic H 2 O-to-H 2 energy-storage process to lose its intrinsic clean, non-carbon feature. These problems seriously influence the progress and realization of solar hydrogen production. Great efforts have been made to develop new catalysts for H 2 -O 2 co-generation, so that sacrificial reductants become unnecessary. 7,[20][21][22][23][24] This strategy seems ideal for the H 2 O-to-H 2 process, but the achievement of efficient, highly stable, and low-cost catalysts appears to require further research. Additionally, the H 2 -O 2 mixture produced may suffer from engineering difficulties in terms of

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