Author Contributions
Conceptualization, A.A.M.; data curation, N.M.A.; formal analysis, N.M.A. and H.M.A.-q.; investigation, N.M.A., M.M.F. and A.A.M.; methodology, A.A.M.; project administration, A.A.M.; resources, N.M.A., H.M.A.-q. and A.A.M.; software, N.M.A. and H.M.A.-q.; supervision, A.A.M.; validation, M.M.F.; visualization, N.M.A., M.M.F. and H.M.A.-q.; writing—original draft, N.M.A.; writing—review and editing, M.M.F., H.M.A.-q. and A.A.M. All authors have read and agreed to the published version of the manuscript.
Figure 1.
(a) Top and side view of the optimized atomic structure of a pristine hexagonal 3 × 3 supercell of a BC6N sheet. The black parallelogram marks the original unit cell of BC6N. Yellow, green, and blue spheres represent C, B, and N atoms, respectively. Bond lengths are given in Å. The numbers “1” (top on N (TN)), “2” (top on B (TB)), “3” (top on BNC hexagonal (H1)), and “4” (top on C hexagonal (H2)) indicate the adsorption sites of gases on the BC6N, whereas the circles refer to the doping sites where the systems are doped with a Pt atom. (b) Projected DOS (PDOS) of the pristine BC6N system showing the most significant contributions.
Figure 1.
(a) Top and side view of the optimized atomic structure of a pristine hexagonal 3 × 3 supercell of a BC6N sheet. The black parallelogram marks the original unit cell of BC6N. Yellow, green, and blue spheres represent C, B, and N atoms, respectively. Bond lengths are given in Å. The numbers “1” (top on N (TN)), “2” (top on B (TB)), “3” (top on BNC hexagonal (H1)), and “4” (top on C hexagonal (H2)) indicate the adsorption sites of gases on the BC6N, whereas the circles refer to the doping sites where the systems are doped with a Pt atom. (b) Projected DOS (PDOS) of the pristine BC6N system showing the most significant contributions.
Figure 2.
(a–d) Top and side view of the optimized atomic structure of Pt-BC6N sheet with different doping sites, PtB, PtC1, PtC2, and PtN, respectively. The purple sphere represents the Pt atom. (e–h) The corresponding DOS/projected DOS (PDOS) of the Pt-BC6N system shows the most significant contributions. (i–l) The corresponding band structure, from −2 eV to 2 eV. Spin-up (down) is in blue (red).
Figure 2.
(a–d) Top and side view of the optimized atomic structure of Pt-BC6N sheet with different doping sites, PtB, PtC1, PtC2, and PtN, respectively. The purple sphere represents the Pt atom. (e–h) The corresponding DOS/projected DOS (PDOS) of the Pt-BC6N system shows the most significant contributions. (i–l) The corresponding band structure, from −2 eV to 2 eV. Spin-up (down) is in blue (red).
Figure 3.
Top and side view of the optimized atomic structure of NO@BC6N sheet with different doping sites: (a) NO@BBC6N, (b) NO@NBC6N, (c) NO@H1BC6N and (d) NO@H2BC6N. (e–h) The corresponding DOS/projected DOS (PDOS) of the NO@BC6N systems. The red spheres represent O atoms.
Figure 3.
Top and side view of the optimized atomic structure of NO@BC6N sheet with different doping sites: (a) NO@BBC6N, (b) NO@NBC6N, (c) NO@H1BC6N and (d) NO@H2BC6N. (e–h) The corresponding DOS/projected DOS (PDOS) of the NO@BC6N systems. The red spheres represent O atoms.
Figure 4.
(a–d) Top and side view of the optimized atomic structure of NO@Pt-BC6N sheet with different doping sites: (a) NO@PtB-BC6N, (b) NO@PtC1-BC6N, (c) NO@PtC2-BC6N, and (d) NO@PtN-BC6N. (e–h) The corresponding DOS/projected DOS (PDOS) and (i–l) the corresponding charge densities of the NO@Pt-BC6N systems. Isosurface yellow (blue) color represents higher (lower) charge density.
Figure 4.
(a–d) Top and side view of the optimized atomic structure of NO@Pt-BC6N sheet with different doping sites: (a) NO@PtB-BC6N, (b) NO@PtC1-BC6N, (c) NO@PtC2-BC6N, and (d) NO@PtN-BC6N. (e–h) The corresponding DOS/projected DOS (PDOS) and (i–l) the corresponding charge densities of the NO@Pt-BC6N systems. Isosurface yellow (blue) color represents higher (lower) charge density.
Figure 5.
(a–d) Top and side view of the optimized atomic structure of NO2@Pt-BC6N sheet with different doping sites: (a) NO2@PtB-BC6N, (b) NO2@PtC1-BC6N, (c) NO2@PtC2-BC6N, and (d) NO2@PtN-BC6N. (e–h) The corresponding DOS/projected DOS (PDOS) and (i–l) the corresponding charge densities of the NO2@Pt-BC6N systems. Isosurface yellow (blue) color represents higher (lower) charge density.
Figure 5.
(a–d) Top and side view of the optimized atomic structure of NO2@Pt-BC6N sheet with different doping sites: (a) NO2@PtB-BC6N, (b) NO2@PtC1-BC6N, (c) NO2@PtC2-BC6N, and (d) NO2@PtN-BC6N. (e–h) The corresponding DOS/projected DOS (PDOS) and (i–l) the corresponding charge densities of the NO2@Pt-BC6N systems. Isosurface yellow (blue) color represents higher (lower) charge density.
Figure 6.
(a–d) Top and side view of the optimized atomic structure of CO2@Pt-BC6N sheet with different doping sites: (a) CO2@PtB-BC6N, (b) CO2@PtC1-BC6N, (c) CO2@PtC2-BC6N, and (d) CO2@PtN-BC6N. (e–h) The corresponding DOS/projected DOS (PDOS) of the CO2@Pt-BC6N systems. (i–l) The corresponding charge density. Isosurface yellow (blue) color represents higher (lower) charge density.
Figure 6.
(a–d) Top and side view of the optimized atomic structure of CO2@Pt-BC6N sheet with different doping sites: (a) CO2@PtB-BC6N, (b) CO2@PtC1-BC6N, (c) CO2@PtC2-BC6N, and (d) CO2@PtN-BC6N. (e–h) The corresponding DOS/projected DOS (PDOS) of the CO2@Pt-BC6N systems. (i–l) The corresponding charge density. Isosurface yellow (blue) color represents higher (lower) charge density.
Figure 7.
(a–d) Top and side view of the optimized atomic structure of NH3@Pt-BC6N sheet with different doping sites: (a) NH3@PtB-BC6N, (b) NH3@PtC1-BC6N, (c) NH3@PtC2-BC6N, and (d) NH3@PtN-BC6N. (e–h) The corresponding DOS/projected DOS (PDOS) and (i–l) the corresponding charge densities of the NH3@Pt-BC6N systems. Isosurface yellow (blue) color represents higher (lower) charge density. In (l), the isosurface extends to the supercell border, and the green color indicates the interior of the isosurface.
Figure 7.
(a–d) Top and side view of the optimized atomic structure of NH3@Pt-BC6N sheet with different doping sites: (a) NH3@PtB-BC6N, (b) NH3@PtC1-BC6N, (c) NH3@PtC2-BC6N, and (d) NH3@PtN-BC6N. (e–h) The corresponding DOS/projected DOS (PDOS) and (i–l) the corresponding charge densities of the NH3@Pt-BC6N systems. Isosurface yellow (blue) color represents higher (lower) charge density. In (l), the isosurface extends to the supercell border, and the green color indicates the interior of the isosurface.
Table 1.
Pt-BC6N: the charge transfer ( (e)), formation energy ( (meV)), magnetization (Mag ()), band gap (Eg (eV)).
Table 1.
Pt-BC6N: the charge transfer ( (e)), formation energy ( (meV)), magnetization (Mag ()), band gap (Eg (eV)).
Systems | | | Mag | (up) | (dn) |
---|
BC6N | - | - | 0.0 | 1.3 | 1.3 |
PtB-BC6N | 0.08 | 87 | 0.9 | 0.2 | 1.3 |
PtC1-BC6N | 0.10 | 88 | 0.0 | 1.1 | 1.1 |
PtC2-BC6N | 0.43 | 94 | 0.0 | 0.5 | 0.5 |
PtN-BC6N | 0.39 | 51 | 1.0 | 0.2 | 1.4 |
Table 2.
NO adsorption NO pristine and Pt-BC6N: the closest distance (d (Å)), nearest atom (X), charge transfer ( (e)), adsorption energy ( (eV)), magnetization (Mag ()), band gap ( (eV)).
Table 2.
NO adsorption NO pristine and Pt-BC6N: the closest distance (d (Å)), nearest atom (X), charge transfer ( (e)), adsorption energy ( (eV)), magnetization (Mag ()), band gap ( (eV)).
Systems | d | X | | | Mag | (up) | (dn) |
---|
@TBBC6N | 2.8 | N | −0.04 | 0.2 | 1.0 | 0.4 | 1.1 |
@TNBC6N | 3.1 | N | 0.00 | 0.1 | 1.0 | 1.1 | 0.4 |
@H1BC6N | 3.1 | N | −0.04 | 0.1 | 1.0 | 0.3 | 1.2 |
@H2BC6N | 2.9 | N | −0.05 | 0.2 | 1.0 | 0.5 | 1.3 |
@PtB-BC6N | 1.9 | N | −0.20 | 2.7 | 2.1 | 1.1 | 0.8 |
@PtC1-BC6N | 1.9 | N | −0.21 | 2.3 | 1.0 | 0.9 | 0.9 |
@PtC2-BC6N | 1.9 | N | −0.15 | 2.3 | 0.7 | 0.2 | - |
@PtN-BC6N | 2.0 | N | −0.20 | 2.1 | 2.1 | 1.2 | 0.9 |
Table 3.
NO2 adsorption on pristine and PtBC6N: the closest distance (d (Å)), O-N-O angle (), nearest atom (X), charge transfer ( (e)), adsorption energy ( (eV)), magnetization (Mag ()), and band gap ( (up) and down (dn) (eV)).
Table 3.
NO2 adsorption on pristine and PtBC6N: the closest distance (d (Å)), O-N-O angle (), nearest atom (X), charge transfer ( (e)), adsorption energy ( (eV)), magnetization (Mag ()), and band gap ( (up) and down (dn) (eV)).
Systems | d | | X | | | Mag | (up) | (dn) |
---|
@TBBC6N | 2.9 | 126.7 | O | −0.07 | 0.1 | 0.9 | 1.4 | - |
@TNBC6N | 3.0 | 126.9 | O | −0.16 | 0.1 | 0.9 | 1.4 | - |
@H1BC6N | 3.0 | 126.9 | O | −0.08 | 0.1 | −0.9 | - | 1.3 |
@H2BC6N | 2.8 | 128.6 | N | −0.11 | 0.1 | 0.9 | 0.3 | 1.3 |
@PtB-BC6N | 2.0 | 112.3 | O | −0.43 | 3.0 | 0.0 | 1.3 | 1.3 |
@PtC1-BC6N | 2.1 | 123.3 | N | −0.34 | 2.5 | 0.2 | - | - |
@PtC2-BC6N | 2.0 | 124.8 | N | −0.30 | 2.5 | 0.0 | - | - |
@PtN-BC6N | 2.3 | 111.8 | O | −0.41 | 3.3 | 0.0 | 1.2 | 1.2 |
Table 4.
CO2 adsorption on pristine and Pt-BC6N: The closest distance (d (Å)), O-C-O angle (), nearest atom (X), charge transfer ( (e)), adsorption energy ( (eV)), magnetization (Mag ()), and band gap ( (up) and down (dn) (eV)).
Table 4.
CO2 adsorption on pristine and Pt-BC6N: The closest distance (d (Å)), O-C-O angle (), nearest atom (X), charge transfer ( (e)), adsorption energy ( (eV)), magnetization (Mag ()), and band gap ( (up) and down (dn) (eV)).
Systems | d | | X | | | Mag | (up) | (dn) |
---|
@TBBC6N | 3.3 | 179.3 | C | −0.02 | 0.2 | 0.0 | 1.3 | 1.3 |
@TNBC6N | 3.2 | 179.8 | C | −0.01 | 0.2 | 0.0 | 1.3 | 1.3 |
@H1BC6N | 3.2 | 179.3 | C | −0.02 | 0.2 | 0.0 | 1.3 | 1.3 |
@H2BC6N | 3.2 | 179.3 | C | −0.02 | 0.2 | 0.0 | 1.3 | 1.3 |
@PtB-BC6N | 2.2 | 144.0 | C | −0.38 | 0.7 | 1.0 | 1.0 | 0.8 |
@PtC1-BC6N | 2.1 | 141.5 | C | −0.42 | 0.8 | 0.0 | 1.1 | 1.1 |
@PtC2-BC6N | 2.1 | 141.0 | C | −0.42 | 0.6 | 0.0 | 0.4 | 0.4 |
@PtN-BC6N | 2.2 | 146.4 | C | −0.33 | 0.4 | 1.0 | 1.0 | 0.9 |
Table 5.
NH3 adsorption on pristine and Pt-BC6N: the closest distance (d (Å)), H-N-H angle (), nearest atom (X), charge transfer ( (e)), adsorption energy ( (eV)), magnetization (Mag ()), and band gap ( (up) and down (dn) (eV)).
Table 5.
NH3 adsorption on pristine and Pt-BC6N: the closest distance (d (Å)), H-N-H angle (), nearest atom (X), charge transfer ( (e)), adsorption energy ( (eV)), magnetization (Mag ()), and band gap ( (up) and down (dn) (eV)).
Systems | d | | X | | | Mag | (up) | (dn) |
---|
@TBBC6N | 2.7 | 102.2 | H | −0.01 | 0.2 | 0.0 | 1.3 | 1.3 |
@TNBC6N | 2.7 | 106.4 | H | −0.01 | 0.2 | 0.0 | 1.3 | 1.3 |
@H1BC6N | 2.7 | 106.2 | H | −0.01 | 0.2 | 0.0 | 1.3 | 1.3 |
@H2BC6N | 2.8 | 106.2 | H | −0.01 | 0.2 | 0.0 | 1.3 | 1.3 |
@PtB-BC6N | 2.2 | 107.3 | N | 0.22 | 1.5 | −0.9 | 1.3 | 0.2 |
@PtC1-BC6N | 2.2 | 107.1 | N | 0.23 | 1.6 | 0.0 | 1.1 | 1.1 |
@PtC2-BC6N | 2.3 | 107.3 | N | 0.21 | 1.3 | 0.0 | 0.7 | 0.7 |
@PtN-BC6N | 2.3 | 106.9 | N | 0.22 | 1.2 | 0.9 | - | 1.4 |
Table 6.
Average adsorption energies ( (eV)) on the Pt-doped systems. The average is taken over the 4 different adsorption sites in each system.
Table 6.
Average adsorption energies ( (eV)) on the Pt-doped systems. The average is taken over the 4 different adsorption sites in each system.
Gas | |
---|
NO2 | 2.8 |
NO | 2.4 |
NH3 | 1.4 |
CO2 | 0.6 |