OXIDATION
REDUCTANT
ELECTRONS
RECOVERY
OXIDANT
D
G
U
P
I
K
D
U
N
S
F
V
E
L
E
C
T
R
O
N
S
I
J
R
O
G
S
G
Y
F
N
R
D
J
O
X
Z
E
N
R
V
O
E
X
O
O
I
U
S
I
E
O
I
D
G
M
A
D
T
I
I
V
E
T
U
S
Z
N
A
Y
R
I
O
O
A
C
U
H
P
N
P
A
G
C
A
D
T
Z
A
L
T
W
U
X
E
D
I
A
S
R
I
A
U
C
J
R
I
X
N
H
Q
Q
I
F
S
N
A
G
O
T
U
