In Figure 5a, the photocatalytic degradation of 0.1
ZnCo2O4/Ag3PO4was analyzed using UV-vis full wave scanning of methyl orange molecules.
The results showed that the characteristic peak intensity of methyl
orange molecules decreased with the prolongation of reaction time near
464nm, and after 30 minutes, its peak intensity approached 0, indicating
that methyl orange had been completely degraded. Fig. 5b shows the
photocatalytic degradation of MO by different catalysts
Ag3PO4,
ZnCo2O4, 0.1
ZnCo2O4/Ag3PO4,
0.2
ZnCo2O4/Ag3PO4,
and 0.3
ZnCo2O4/Ag3PO4.
The results showed that the photocatalytic effect of pure
ZnCo2O4 was the worst, and the
photocatalytic degradation rate was only 5% within 30 min. While
Ag3PO4, 0.2
ZnCo2O4/Ag3PO4,
and 0.3
ZnCo2O4/Ag3PO4showed 56%, 69%, and 65% photocatalytic degradation at 30 min,
respectively. The results showed that the 0.1ZnCo2O4/Ag3PO4 catalyst had
the best photocatalytic degradation effect on methyl orange, and after
30 minutes, the degradation rate of methyl orange could reach 94%. This
study found that ZnCo2O4 can effectively
improve the photocatalytic degradation performance of
Ag3PO4. Fig. 5c shows that the reaction
of
ZnCo2O4/Ag3PO4photocatalytic degradation of methyl orange follows the pseudo
first-order reaction kinetic model. As shown in Table 3, calculate the
k-value of each sample after linearly fitting the curve, and the
reaction rate constants of Ag3PO4,
ZnCo2O4, 0.1
ZnCo2O4/Ag3PO4,
0.2
ZnCo2O4/Ag3PO4,
and 0.3
ZnCo2O4/Ag3PO4were 0.01793min-1, 0.00102min-1,
0.05301min-1, 0.0229min-1 and
0.0206min-1, respectively. The maximum reaction rate
constant of 0.1
ZnCo2O4/Ag3PO4is 0.05301min-1, which is 3 times that of
Ag3PO4 and 52 times that of
ZnCo2O4. These results indicate that the
combination of Ag3PO4 and
ZnCo2O4 has a synergistic effect, which
can improve its photocatalytic performance. Figure 5d shows the test of
stability consequences of Ag3PO4 and
0.1ZnCo2O4/Ag3PO4recycled three times. From the figure, it can be seen that after three
rounds of recycling, the degradation rate of MO by
Ag3PO4 is only 21.8%, while the
degradation rate of Mo by 0.1
ZnCo2O4/Ag3PO4is 84.4%, which indicates that the use of
Ag3PO4 and
ZnCo2O4 for compounding can improve the
stability of the photocatalyst.
Figure6Trapping experiments of active species during photocatalysis reaction.
Fig. 6 shows the effect of different capture factors on the reaction
rate of 0.1
ZnCo2O4/Ag3PO4photocatalytic degradation of MO. From the figure, it can be seen that
the addition of IPA has little influence on the photocatalytic
degradation of MO. It can be seen that in the photocatalytic degradation
of MO by 0.1
ZnCo2O4/Ag3PO4,
holes (h+) and superoxide ions (O-2· ) play the most important roles in the photocatalytic
degradation, and hydroxyl radicals (OH·) play a partial role in the
degradation.