Table 2 Experimental matrix of central composite design runs using Design Expert 8.0 software
Run order no. | Factors variables | Current density (mA cm−2) | ||
|---|---|---|---|---|
X1:NaOH concentration (M) | X2: Temperature (°C) | X3: Catalyst loading | Actual | |
1 | 0.5 | 80 | 30 | 115.89 |
2 | 3.25 | 6.25 | 20 | 35.89 |
3 | 3.25 | 52.5 | 20 | 160.7 |
4 | 0.1 | 52.5 | 20 | 113 |
5 | 6 | 25 | 10 | 75.62 |
6 | 3.25 | 52.5 | 6.25 | 32.33 |
7 | 3.25 | 98.74 | 20 | 105.05 |
8 | 3.25 | 52.5 | 20 | 150.98 |
9 | 0.5 | 25 | 10 | 38.62 |
10 | 6 | 25 | 30 | 90 |
11 | 6 | 80 | 10 | 101.1 |
12 | 3.25 | 52.5 | 36 | 68.98 |
13 | 0.5 | 80 | 10 | 110.65 |
14 | 6 | 80 | 30 | 119.56 |
15 | 3.25 | 52.5 | 20 | 159.7 |
16 | 3.25 | 52.5 | 20 | 152.69 |
17 | 7.87 | 52.5 | 20 | 164 |
18 | 3.25 | 52.5 | 20 | 158.9 |
19 | 0.5 | 25 | 30 | 60 |
20 | 3.25 | 52.5 | 20 | 163.25 |