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A systematic computational study of surface reactivity for pure and mono-hydrogenated carbon nanocoes (CNCs) formed from graphene sheets as functions of disclination angle, cone size and hydrogenation sites has been investigated through density functional (DFT) calculations and at the B3LYP/3-21G level of theory. Five disclination angles (60°, 120°, 180°, 240° and 300°) are applied and at any disclination angle four structures with different sizes are studied. For comparison, pure and mono-hydrogenated boron nitride nanocones (BNNCs) with disclination angles 60°, 120°, 180°, 240° and 300° are also investigated. The hydrogenation is done on three different sites, H
^{S1} (above the first neighbor atom of the apex atoms), H
^{S2} (above one atom of the apex atoms) and H
^{S3} (above one atom far from the apex atoms). Our calculations show that the highest surface reactivity for pure CNCs and BNNCs at disclination angles 60°, 180° and 300° is 23.50 Debye for B
_{41}N
_{49}H
_{10} cone and at disclination angles 120° and 240° is 15.30 Debye for C
_{94}H
_{14} cone. For mono-hydrogenated CNCs, the highest surface reactivity is 22.17 Debye for C
_{90}H
_{10}-H
^{S3} cone at angle 300° and for mono-hydrogenated BNNCs the highest surface reactivity is 28.97 Debye for B
_{41}N
_{49}H
_{10}-H
^{S1} cone when the hydrogen atom is adsorbed on boron atom at cone angle 240°.

The hallow shape and the curvature of CNTs that are not present in bulk graphite make them easier to storage hydrogen inside and outside the tube surface. At the same line, one of the most important applications of CNCs (representing the fifth allotropic form of carbon) is hydrogen storage. Hydrogen storage on CNCs has been explored theoretically [^{S1} (above the first neighbor atom of the apex atoms), H^{S2} (above one atom of the apex atoms) and H^{S3} (above one atom far from the apex atoms). Hopefully, these results could be useful for testing the capability of CNCs and BNNs as hydrogen storage systems.

Density Functional Theory (DFT) calculations have been performed employing the B3LYP exchange-correla- tion functional [^{S1} (above the first neighbor

atom of the apex atoms), H^{S2} (above one atom of the apex atoms) and H^{S3} (above one atom far from the apex atoms). To avoid the dangling effects, the hydrogen atoms have been used to saturate the ending atoms for CNCs and BNNCs. All the atomic geometries of pure and mono-hydrogenated CNCs and BNNCs have been allowed to fully relaxation during the optimization processes.

The CNCs are consisting of curved graphite sheets formed as open cones and are constructed by cutting out sectors of n × 60˚ (n = 1 - 5) from the flat sheet of graphene and connecting the edges. In the present work, we have investigated cone 60˚ (a five-membered ring at the apex), cone 120˚ (a four-membered ring), cone 180˚ (a three-memberedring), cone 240˚ (a bicyclic system), and cone 300˚ (a complex with a three-membered and four- membered rings at the apex), see Figures 1(a)-(e). At the same line the BNNCs are constructed, see Figures 1(f)-(j). For all CNCs and BNNCs with disclination angles 120˚ and 240˚, there is only one model. However, for BNNCs with disclination angles 60˚, 180˚, and 300˚ there are two models (M1 and M2), resulting from the connected atoms edges can be either nitrogen atoms (named M1) or can be boron atoms (named M2).

The surface reactivity of pure CNCs and BNNCs at different disclination angels n × 60˚ (n = 1 to 5) are studied. Also, at any disclination angle the effect of the cone size is tested through working on four different structures. By this way, one can test the effects of size, disclination angle and types of NCs on the surface reactivity of NCs.

The surface reactivity of CNCs and BNNCs at disclination angle 60˚ is investigated and is listed in _{82}N_{87}H_{30} (M1) cone 60˚ possesses the highest surface reactivity (13.1 Debye), followed by C_{169}H_{30} cone 60˚ (12.1 Debye) and the smallest surface reactivity is for B_{87}N_{82}H_{30} (M2) cone 60˚ (7.1 Debye). In other words, by increasing the number of nitrogen atoms (in case of the type of connected atoms edges is nitrogen atoms) and decreasing the number of boron atoms, the surface reactivity of BNNCs is increased.

_{136}H_{24} cone 120˚ (13.6 Debye) is higher than the surface reactivity of B_{68}N_{68}H_{24} cones 120˚ (9.2 Debye). This indicates that when the number of boron atoms is equal to number of nitrogen atoms (i.e. type of connected atoms edges is both of nitrogen and boron atoms), the surface reactivity of BNNCs is reduced. From

The surface reactivity of CNCs and BNNCs at disclination angle 180˚ is listed in

Stoichiometry cones 60˚ | N | M | Y | C_{n+m}H_{y} | B_{n}N_{m}H_{y} M1 | B_{m}N_{n}H_{y} M2 |
---|---|---|---|---|---|---|

Dipole moment/Debye | ||||||

St1 | 21 | 24 | 15 | 5.4 | 7.2 | 4.9 |

St2 | 38 | 42 | 20 | 7.9 | 9.5 | 5.5 |

St3 | 56 | 59 | 25 | 9.2 | 9.8 | 6.6 |

St4 | 82 | 87 | 30 | 12.1 | 13.1 | 7.1 |

M1 refers to the type of connected atoms edges is nitrogen atoms, M2 refers to the type of connected atoms edges is boron atoms.

Stoichiometry cones 120˚ | M | Y | C_{2m}H_{y} | B_{m}N_{m}H_{y} |
---|---|---|---|---|

Dipole moment/Debye | ||||

St1 | 18 | 12 | 6.1 | 5.1 |

St2 | 28 | 16 | 8.0 | 5.7 |

St3 | 46 | 20 | 10.7 | 7.5 |

St4 | 68 | 24 | 13.6 | 9.2 |

Stoichiometry cones 180˚ | N | M | Y | C_{n+m}H_{y} | B_{n}N_{m}H_{y} M1 | B_{m}N_{n}H_{y} M2 |
---|---|---|---|---|---|---|

Dipole moment/Debye | ||||||

St1 | 22 | 26 | 12 | 7.8 | 12.1 | 7.1 |

St2 | 35 | 40 | 15 | 9.3 | 13.1 | 8.9 |

St3 | 49 | 53 | 18 | 9.8 | 15.2 | 9.4 |

St4 | 68 | 73 | 21 | 11.5 | 15.9 | 11.2 |

B_{68}N_{73}H_{21} (M1) cone 180˚ possesses the highest surface reactivity (15.9 Debye), followed by C_{141}H_{21} cone 180˚ (11.5 Debye) and the smallest surface reactivity is for B_{73}N_{68}H_{21} (M2) cone 180˚ (11.2 Debye). In addition, the surface reactivity of cones 180˚ is found to be higher than the surface reactivity of the cones 120˚ and the latter is higher than the cones 60˚.

From _{94}H_{14} cone 240˚ (15.3 Debye) is higher than the surface reactivity of B_{47}N_{47}H_{14} cone 240˚ (11.9 Debye). From Tables 1-4, it is clear that by increasing the disclination angle (from cones 60˚ to cones 240˚), the surface reactivity is increased.

The surface reactivity of CNCs and BNNCs at disclination angle 300˚ is shown in _{41}N_{49}H_{10} (M1) cone 300˚ possesses the highest surface reactivity (23.5 Debye), followed by C_{90}H_{10} cone 300˚ (23.5 Debye) and the smallest surface reactivity is for B_{49}N_{41}H_{10} (M2) cone 300˚ (12.5 Debye).

From Tables 1-5, one can report that the surface reactivity is increased by increasing the cone size and the disclination angle. In addition, the highest surface reactivity is for B_{n}N_{m}H_{y} (M1) cones when the type of connected atoms edges is nitrogen atoms (at disclination angles 60˚, 180˚ and 300˚), otherwise the surface reactivity of C_{2m}H_{y} cones is always higher than B_{m}N_{m}H_{y} cones (at disclination angles 120˚ and 240˚).

The surface reactivity of mono-hydrogenated CNCs at three different hydrogenation sites H^{S1} (above the first neighbor atom of the apex atoms), H^{S2} (above one atom of the apex atoms) and H^{S3} (above one atom far from the apex atoms) for each disclination angels n × 60˚ (n = 1 to 5) are studied, see ^{S3} always possesses the highest dipole moment, followed by H^{S1} and H^{S2} sites. The highest surface reactivities at disclination angles 60˚, 120˚, 180˚, 240˚ and 300˚ are found to be 10.94 Debye for C_{170}H_{30}-H^{S1}, 12.58 Debye for C_{136}H_{24}-H^{S3}, 18.70 Debye for C_{141}H_{21}-H^{S1}, 16.98 Debye for C_{94}H_{14}-H^{S3} and 22.17 Debye for C_{90}H_{10}-H^{S3}, respectively. Finally, on can conclude that the best cone size, the best hydrogenation site and best disclination angle for hydrogen adsorption is for CNC C_{90}H_{10}-H^{S3} at 300˚ declination angle.

Stoichiometry cones 240˚ | M | Y | C_{2m}H_{y} | B_{m}N_{m}H_{y} |
---|---|---|---|---|

Dipole moment/Debye | ||||

St1 | 14 | 8 | 8.0 | 7.9 |

St2 | 23 | 10 | 11.8 | 9.0 |

St3 | 34 | 12 | 12.0 | 10.0 |

St4 | 47 | 14 | 15.3 | 11.9 |

Stoichiometry cones 300˚ | N | M | Y | C_{n+m}H_{y} | B_{n}N_{m}H_{y} M1 | B_{m}N_{n}H_{y} M2 |
---|---|---|---|---|---|---|

Dipole moment/Debye | ||||||

St1 | 15 | 19 | 6 | 11.2 | 11.7 | 8.0 |

St2 | 21 | 26 | 7 | 12.8 | 13.4 | 10.4 |

St3 | 34 | 41 | 9 | 18.6 | 19.0 | 10.9 |

St4 | 41 | 49 | 10 | 21.9 | 23.5 | 12.5 |

Angle 60˚ | Angle 120˚ | Angle 180˚ | Angle 240˚ | Angle 300˚ | |||||
---|---|---|---|---|---|---|---|---|---|

Systems | Dipole moment | Systems | Dipole moment | Systems | Dipole moment | Systems | Dipole moment | Systems | Dipole moment |

C_{45}H_{15}-H^{S1} C_{45}H_{15}-H^{S2} C_{45}H_{15}-H^{S3} | 5.63 3.65 5.02 | C_{36}H_{12}-H^{S1} C_{36}H_{12}-H^{S2} C_{36}H_{12}-H^{S3} | 5.87 4.93 6.11 | C_{48}H_{12}-H^{S1 } C_{48}H_{12}-H^{S2} C_{48}H_{12}-H^{S3} | 7.60 7.17 8.43 | C_{28}H_{8}-H^{S1 } C_{28}H_{8}-H^{S2} C_{28}H_{8}-H^{S3} | 3.16 3.68 5.54 | C_{23}H_{5}-H^{S1} C_{23}H_{5}-H^{S2} C_{23}H_{5}-H^{S3} | 3.22 2.46 5.88 |

C_{80}H_{20}-H^{S1} C_{80}H_{20}-H^{S2} C_{80}H_{20}-H^{S3}^{ } | 6.92 6.03 7.09 | C_{56}H_{16}-H^{S1} C_{56}H_{16}-H^{S2 } C_{56}H_{16}-H^{S3} | 6.94 6.38 7.42 | C_{75}H_{15}-H^{S1} C_{75}H_{15}-H^{S2} C_{75}H_{15}-H^{S3} | 12.73 10.46 11.26 | C_{46}H_{10}-H^{S1 } C_{46}H_{10}-H^{S2}_{ } C_{46}H_{10}-H^{S3}_{ } | 6.67 6.01 6.93 | C_{34}H_{6}-H^{S1 } C_{34}H_{6}-H^{S2} C_{34}H_{6}-H^{S3} | 10.31 6.72 10.42 |

C_{115}H_{25}-H^{S1 } C_{115}H_{25}-H^{S2} C_{115}H_{25}-H^{S3} | 9.14 6.64 7.94 | C_{92}H_{20}-H^{S1 } C_{92}H_{20}-H^{S2 } C_{92}H_{20}-H^{S3} | 8.49 8.78 10.38 | C_{102}H_{18}-H^{S1 } C_{102}H_{18}-H^{S2} C_{102}H_{18}-H^{S3} | 11.23 11.65 11.98 | C_{68}H_{12}-H^{S1 } C_{68}H_{12}-H^{S2}_{ } C_{68}H_{12}-H^{S3}_{ } | 5.92 7.81 8.53 | C_{58}H_{8}-H^{S1} C_{58}H_{8}-H^{S2} C_{58}H_{8}-H^{S3} | 15.61 12.39 13.28 |

C_{170}H_{30}-H^{S1 } C_{170}H_{30}-H^{S2} C_{170}H_{30}-H^{S3} | 10.94 9.52 10.79 | C_{136}H_{24}-H^{S1 } C_{136}H_{24}-H^{S2} C_{136}H_{24}-H^{S3} | 12.18 11.52 12.58 | C_{141}H_{21}-H^{S1 } C_{141}H_{21}-H^{S2 } C_{141}H_{21}-H^{S3} | 18.70 15.99 15.55 | C_{94}H_{14}-H^{S1 } C_{94}H_{14}-H^{S2}_{ } C_{94}H_{14}-H^{S3}_{ } | 6.73 7.51 16.98 | C_{90}H_{10}-H^{S1 } C_{90}H_{10}-H^{S2} C_{90}H_{10}-H^{S3} | 18.38 17.93 22.17 |

H^{S1} refers to the hydrogenation site is above the first neighbor atom of the apex atoms. H^{S2} refers to the hydrogenation site is above one atom of the apex atoms. H^{S3} refers to the hydrogenation site is above one atom far from the apex atoms.

Also, the surface reactivity of mono-hydrogenated BNNCs at three different hydrogenation sites H^{S1}, H^{S2} and H^{S3} for each disclination angels n × 60˚ (n = 1 to 5), are studied. The hydrogen atom can be adsorbed on boron atom (named Type1) or can be adsorbed on nitrogen atom (named Type2). As we mention above, for disclination angles 60˚, 180˚ and 300˚ there are two models of BNNCs, BNNCs-M1 (the connected edges atoms are nitrogen atoms) and BNNCs-M2 (the connected edges atoms are boron atoms). Therefore, for the surface reactivity of BNNCs at disclination angles 120˚ and 240˚ for there are two systems of BNNCs, BNNCs-Type1 and BNNCs-Type2, see

From

are increased by increasing the cone size and cone angle. For disclination angle 120˚, the highest surface reactivates for Type1 and Type2 are found to be 10.90 Debye for B_{68}N_{68}H_{24}-H^{S2} and 11.75 Debye for B_{68}N_{68}H_{24}-H^{S1}, respectively. For disclination angle 240˚, the highest surface reactivates for Type1 and Type2 are found to be 12.85 Debye for B_{47}N_{47}H_{14}-H^{S2} and 25.20 Debye for B_{34}N_{34}H_{12}-H^{S3}, respectively.

_{38}N_{42}H_{20}-H^{S2} and 10.77 Debye for B_{83}N_{87}H_{30}-H^{S1}, respectively. For disclination angle 180˚, the highest surface reactivates for Type1 and Type2 are found to be 20.81 Debye for B_{68}N_{73}H_{21}-H^{S1} and 28.50 Debye for B_{35}N_{40}H_{15}-H^{S3}, respectively. For disclination angle 300˚, the highest surface reactivates for Type1 and Type2 are found to be 28.97 Debye for B_{41}N_{49}H_{10}-H^{S1} and 27.55 Debye for B_{26}N_{32}H_{8}-H^{S3}, respectively.

From _{87}N_{83}H_{30}-H^{S2} and 20.77 Debye for B_{42}N_{38}H_{20}-H^{S1}, respectively. For disclination angle 180˚, the highest surface reactivates for Type1 and Type2 are found to be 11.83 Debye and 17.28 Debye B_{73}N_{68}H_{21}-H^{S3}, respectively. For disclination angle 300˚, the highest surface reactivates for Type1 and Type2 are found to be 7.26 Debye and 25.94 Debye for B_{32}N_{26}H_{8}-H^{S3}, respectively. We can conclude that the best cone size, the best hydrogenation site and best disclination angle for mono-hydrogenated Type1 and Type2 of BNNCs is 28.97 Debye for B_{41}N_{49}H_{10}-H^{S1} and 27.55 Debye for B_{26}N_{32}H_{8}-H^{S3} at 300˚ declination angle.

Finally, it is found that the surface reactivity for pure and mono-hydrogenated CNCs and BNNCs is increased by increasing the cone angle and the cone size. Also, it is found that the surface reactivity is increased by hydrogenation and the highest surface reactivity is found to be 28.97 Debye for B_{41}N_{49}H_{10}-H^{S1} (M1) when the hydrogenation is done on the boron atom (Type1).

Angle 120˚ | Angle 240˚ | ||||
---|---|---|---|---|---|

Dipole moment | Dipole moment | ||||

Systems | Type1 | Type2 | Systems | Type1 | Type2 |

B_{18}N_{18}H_{12}-H^{S1} B_{18}N_{18}H_{12}-H^{S2} B_{18}N_{18}H_{12}-H^{S3} | 4.70 6.49 5.27 | 7.66 3.45 7.98 | B_{14}N_{14}H_{8}-H^{S1 } B_{14}N_{14}H_{8}-H^{S2} B_{14}N_{14}H_{8}-H^{S3} | 3.43 5.67 5.97 | 8.22 5.67 5.81 |

B_{28}N_{28}H_{16}-H^{S1} B_{28}N_{28}H_{16}-H^{S2 } B_{28}N_{28}H_{16}-H^{S3} | 5.26 7.31 5.58 | 8.34 4.61 3.72 | B_{23}N_{23}H_{10}-H^{S1 } B_{23}N_{23}H_{10}-H^{S2}_{ } B_{23}N_{23}H_{10}-H^{S3}_{ } | 5.24 8.86 7.94 | 10.13 7.69 12.64 |

B_{46}N_{46}H_{20}-H^{S1 } B_{46}N_{46}H_{20}-H^{S2} B_{46}N_{46}H_{20}-H^{S3} | 7.02 9.18 7.49 | 10.09 6.12 6.84 | B_{34}N_{34}H_{12}-H^{S1 } B_{34}N_{34}H_{12}-H^{S2}_{ } B_{34}N_{34}H_{12}-H^{S}^{3}_{ } | 7.10 10.88 10.19 | 11.97 9.60 25.20 |

B_{68}N_{68}H_{24}-H^{S1 } B_{68}N_{68}H_{24}-H^{S2} B_{68}N_{68}H_{24}-H^{S3} | 8.69 10.90 9.18 | 11.75 7.60 6.81 | B_{47}N_{47}H_{14}-H^{S1 } B_{47}N_{47}H_{14}-H^{S2}_{ } B_{47}N_{47}H_{14}-H^{S3}_{ } | 8.91 12.85 11.86 | 13.92 11.45 16.77 |

Angle 60˚ | Angle 180˚ | Angle 300˚ | ||||||
---|---|---|---|---|---|---|---|---|

Dipole moment | Dipole moment | Dipole moment | ||||||

Systems | Type1 | Type2 | Systems | Type1 | Type2 | Systems | Type1 | Type2 |

B_{21}N_{24}H_{15}-H^{S1} B_{21}N_{24}H_{15}-H^{S2} B_{21}N_{24}H_{15}-H^{S3} | 7.20 11.07 7.01 | 7.72 5.88 6.35 | B_{22}N_{26}H_{12}-H^{S1 } B_{22}N_{26}H_{12}-H^{S2} B_{22}N_{26}H_{12}-H^{S3} | 16.37 13.65 15.68 | 13.57 11.70 19.98 | B_{10}N_{13}H_{5}-H^{S1} B_{10}N_{13}H_{5}-H^{S2} B_{10}N_{13}H_{5}-H^{S3} | 19.05 10.19 9.04 | 9.82 10.72 10.41 |

B_{38}N_{42}H_{20}-H^{S1} B_{38}N_{42}H_{20}-H^{S2} B_{38}N_{42}H_{20}-H^{S3}^{ } | 9.47 13.90 9.49 | 10.56 8.03 8.32 | B_{35}N_{40}H_{15}-H^{S1} B_{35}N_{40}H_{15}-H^{S2} B_{35}N_{40}H_{15}-H^{S3} | 19.83 16.63 15.28 | 16.49 14.63 28.50 | B_{15}N_{19}H_{6}-H^{S1 } B_{15}N_{19}H_{6}-H^{S2} B_{15}N_{19}H_{6}-H^{S3} | 11.06 12.56 11.95 | 11.48 11.90 18.29 |

B_{42}N_{56}H_{25}-H^{S1 } B_{42}N_{56}H_{25}-H^{S2} B_{42}N_{56}H_{25}-H^{S3} | 6.73 10.80 6.90 | 8.81 4.82 5.54 | B_{49}N_{53}H_{18}-H^{S1 } B_{49}N_{53}H_{18}-H^{S2} B_{49}N_{53}H_{18}-H^{S3} | 17.78 14.10 13.10 | 14.74 12.32 13.42 | B_{26}N_{32}H_{8}-H^{S1} B_{26}N_{32}H_{8}-H^{S2} B_{26}N_{32}H_{8}-H^{S3} | 22.92 12.03 15.56 | 16.60 11.33 27.55 |

B_{83}N_{87}H_{30}-H^{S1 } B_{83}N_{87}H_{30}-H^{S2} B_{83}N_{87}H_{30}-H^{S3} | 8.87 13.18 8.96 | 10.77 10.95 7.80 | B_{68}N_{73}H_{21}-H^{S1 } B_{68}N_{73}H_{21}-H^{S2 } B_{68}N_{73}H_{21}-H^{S3} | 20.81 16.97 15.90 | 17.41 15.00 15.97 | B_{41}N_{49}H_{10}-H^{S1 } B_{41}N_{49}H_{10}-H^{S2} B_{41}N_{49}H_{10}-H^{S3} | 28.97 16.79 23.17 | 13.07 12.04 20.51 |

Angle 60˚ | Angle 180˚ | Angle 300˚ | ||||||
---|---|---|---|---|---|---|---|---|

Systems | Dipole moment | Systems | Dipole moment | Systems | Dipole moment | |||

Type1 | Type2 | Type1 | Type2 | Type1 | Type2 | |||

B_{24}N_{21}H_{15}-H^{S1} B_{24}N_{21}H_{15}-H^{S2} B_{24}N_{21}H_{15}-H^{S3} | 4.91 5.30 5.17 | 17.20 10.50 4.24 | B_{26}N_{22}H_{12}-H^{S1 } B_{26}N_{22}H_{12}-H^{S2} B_{26}N_{22}H_{12}-H^{S3} | 3.84 7.36 7.37 | 8.54 8.96 17.28 | B_{13}N_{10}H_{5}-H^{S1} B_{13}N_{10}H_{5}-H^{S2} B_{13}N_{10}H_{5}-H^{S3} | 4.49 4.02 1.13 | 3.59 2.39 8.14 |

B_{42}N_{38}H_{20}-H^{S1} B_{42}N_{38}H_{20}-H^{S2} B_{42}N_{38}H_{20}-H^{S3} | 6.78 6.94 6.75 | 20.77 12.24 20.66 | B_{40}N_{35}H_{15}-H^{S1} B_{40}N_{35}H_{15}-H^{S2} B_{40}N_{35}H_{15}-H^{S3} | 5.54 9.21 9.27 | 10.28 10.64 14.37 | B_{19}N_{15}H_{6}-H^{S1 } B_{19}N_{15}H_{6}-H^{S2} B_{19}N_{15}H_{6}-H^{S3} | 5.00 3.67 7.18 | 3.04 7.28 13.85 |

B_{56}N_{42}H_{25}-H^{S1 } B_{56}N_{42}H_{25}-H^{S2} B_{56}N_{42}H_{25}-H^{S3} | 5.38 5.89 5.54 | 16.40 9.43 10.73 | B_{53}N_{49}H_{18}-H^{S1 } B_{53}N_{49}H_{18}-H^{S2} B_{53}N_{49}H_{18}-H^{S3} | 6.61 9.81 9.46 | 12.13 9.64 15.08 | B_{32}N_{26}H_{8}-H^{S1} B_{32}N_{26}H_{8}-H^{S2} B_{32}N_{26}H_{8}-H^{S3} | 5.66 2.80 7.26 | 4.37 3.04 25.94 |

B_{87}N_{83}H_{30}-H^{S1 } B_{87}N_{83}H_{30}-H^{S2} B_{87}N_{83}H_{30}-H^{S3} | 6.92 7.44 7.11 | 9.50 11.27 7.21 | B_{73}N_{68}H_{21}-H^{S1 } B_{73}N_{68}H_{21}-H^{S2 } B_{73}N_{68}H_{21}-H^{S3} | 8.18 11.57 11.83 | 13.74 11.51 11.53 | B_{49}N_{41}H_{10}-H^{S1 } B_{49}N_{41}H_{10}-H^{S2} B_{49}N_{41}H_{10}-H^{S3} | 5.09 2.57 2.57 | 8.73 4.77 14.92 |

The surface reactivity of fifty-two structures of pure CNCs and BNNCs and two hundred and fifty-two structures for mono-hydrogenated CNCs and BNNCs is calculated using density functional (DFT) calculations at the B3LYP/3-21G level of theory. Five disclination angles (60˚, 120˚, 180˚, 240˚ and 300˚), four different nanocone sizes and three different hydrogenation sites are applied. The calculations show that the dipole moments are always increased by increasing the nanocone sizes and the highest surface reactivity for pure CNCs and BNNCs at disclination angles 60˚, 180˚ and 300˚ is 23.50 Debye for B_{41}N_{49}H_{10} cone and at disclination angles 120˚ and 240˚ is 15.30 Debye for C_{94}H_{14} cone. For mono-hydrogenated CNCs, the highest surface reactivity is found 22.17 Debye C_{90}H_{10}-H^{S3} at CNC angle 300˚ and for mono-hydrogenated BNNCs the highest surface reactivity is 28.97 Debye for B_{41}N_{49}H_{10}-H^{S1} when the hydrogen atom is adsorbed on boron atom at BNNC angle 240˚.

Ahlam A.El-Barbary,Mohamed A.Kamel,Khaled M.Eid,Hayam O.Taha,Rasha A.Mohamed,Mohammed A.Al-Khateeb,11, (2015) The Surface Reactivity of Pure and Monohydrogenated Nanocones Formed from Graphene Sheets. Graphene,04,75-83. doi: 10.4236/graphene.2015.44008