N-doped graphene as a catalyst directly or mixed with carbon support to anchor metal catalysts.

The spin density and charge density of atoms are the major factors that determine the catalytic active sites in Oxygen Reduction Reaction (ORR). N-doping introduces unpaired electron, which changes the atomic charge distribution. The active sites in N-doped -graphene are carbon atoms that possess high spin density.

The interaction between Pt atom and N-doped graphene

In N-doped graphene, the nitrogen atoms do not bond with Pt atom directly; instead, they direct a Pt atom to bond with the carbon atom, which is more energetically favoured. This is helpful to prevent Pt nanoclusters from migrating and forming larger particles.

N-doped graphene as a semiconductor

For semiconductors, the flow of electricity needs activation (for example, heat or light absorption) to get over the gap between the valence band and conduction band. Nitrogen doping of <2% can modulate the electrical properties of graphene.

N-doped graphene as a potential anode material in lithium-ion batteries

The introduction of both the pyridinic and quaternary structures and the defects and disordered surface morphology induced by the doping would increase electrode/electrolyte wettability and improved electrochemical performance.

N-doped graphene as a potential electrode material for ultracapacitor

N-graphene-based devices have shown a much higher capacitance than a device based on pristine graphene in both KOH and organic electrolyte. The basal plane pyridinic N exhibits the largest binding energy. Thus, basal-plane pyridinic N has a dominant role in the capacitance enhancement.

N-doped graphene as a potential electrode material for electrochemical sensing

The glucose oxidase (GOx) redox current peak on N-doped graphene can be greatly improved over that of un-doped graphene, which demonstrates enhanced electron transfer efficiency of N-graphene.

N-doped graphene as counter electrode for dye-sensitized solar cells.

N-doped graphene has notably higher catalytic to triiodide reduction but also higher conductivity. The high porosity, hydrophilic wettability and large surface area lead to a higher short circuit current, open-circuit voltage and fill factor. Pyrrolic N and Pyridinic have show lower catalytic activities but higher adsorption energy.

N-doped graphene as a hole transporting material for Perovskite solar cells

N-doped graphene has a higher solution processibility, conductivity better-aligned energy levels and better growth of the crystalline than that of pristine graphene. it can be used as a hole transporting material instead of the traditional poly (ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT:PSS) nickel oxides as a hole-transporting layer.

N-doped graphene as electrical detection

The high carrier density, mobility and tunable electronic properties of graphene by electrostatic charge transfer are the advantages as sensing elements. The nitrogen doping can be more sensitive to absorb gas molecules than pristine graphene, which leads to more change of its conductance, thus higher sensitivity.

N-doped graphene as solute in printing solution

Both the pyridinic and quaternary structures and disordered surface morphology induced by nitrogen doping increase electrode/electrolyte wettability and electrical conductivity, which is beneficial in improving the electrical property of the electrodes.

N-doped graphene as an additive material

The high hydrophilicity of N-doped graphene reinforces hollow fibre polymer membrane with up to 100% increase in permeability and it shows high stability at close to 0oC working temperature and retaining membrane permeability after drying without the need for glycerine post-treatment.

N-doped graphene as an additive material

The thermal and ageing resistances, electrical and mechanical properties of various rubbers and resins can be more uniformly reinforced by N-doped graphene. The hydrophilic property and functional group of nitrogen dopant in graphene can increase the interfacial interactions between graphene and rubber/resin. The N-doped graphene can be dispersed in the rubber/resin matrix more uniformly and create absorption interfaces. It transfers the stress by the interfaces and slows the crack spreading. The functional groups of N doping contribute to forming greater interface adhesion in the polymer matrix by covalent bonding or van der Waals' interaction, which helps decrease the interfacial resistance and generate thermal conductive pathways and networks. Compared with pristine graphene, nitrogen-doped graphene can better inhibit the initial oxidation process of rubber, and improve their anti-aging effect, because of the phenazine structure.