Strain Controlling Catalytic Efficiency …
13
Table 6 Total energies for
single molecules using the
DFT + U functional with D2
van der Waals corrections
D2
Molecule
Etot
H2
−6.773231589
O 2
−9.86541783731
H2O
−14.2244765844
Table 7 Free energy and overpotential calculations for pure NiOOH with DFT + U, HSE, and
DFT + U with D2
Pure
Pure-D2
Pure-HSE
State
Etot (eV)
State
Etot (eV)
State
Etot (eV)
A_pure
−254.429010412
A_pure
−254.429126664
A_pure
−403.173436338
B_pure
−248.950010975
B_pure
−248.949010183
B_pure
−396.980362244
C_pure
−259.104525084
C_pure
−259.104556066
C_pure
−410.996140834
D_pure
−253.910425010
D_pure
−253.910439616
D_pure
−405.034590815
Reaction
Delta E
Reaction
Delta E
Reaction
delta E
1 to 2
2.092383643
1 to 2
2.093500687
1 to 2
2.338537973
2 to 3
0.683346681
2 to 3
0.682314907
2 to 3
1.001480784
3 to 4
1.807484280
3 to 4
1.807500656
3 to 4
2.107013898
4 to 1
0.453857551
4 to 1
0.453755905
4 to 1
−0.128002619
Reaction
Delta G (eV)
Reaction
Delta G (eV)
Reaction
Delta G (eV)
1 to 2
1.72238364
1 to 2
1.723500687
1 to 2
1.968537973
2 to 3
1.11334668
2 to 3
1.112314907
2 to 3
1.431480784
3 to 4
1.42748428
3 to 4
1.427500656
3 to 4
1.727013898
4 to 1
0.24385755
4 to 1
0.243755905
4 to 1
−0.338002619
Overpotential
(eV)
0.61238364
Overpotential
(eV)
0.613500687
Overpotential
(eV)
0.858537973