3.1. Catalyst characterization
Figure 1 The XRD optical spectrum of Ag3PO4, ZnCo2O4, 0.1 ZnCo2O4/Ag3PO4, 0.2 ZnCo2O4/Ag3PO4and 0.3 ZnCo2O4/Ag3PO4.
The XRD spectra of the prepared Ag3PO4, ZnCo2O4, 0.1 ZnCo2O4/Ag3PO4, 0.2 ZnCo2O4/Ag3PO4, and 0.3 ZnCo2O4/Ag3PO4catalysts are shown in Fig. 1. It can be seen from the figure that the diffraction peaks located at 18.96°, 31.22°, 36.81°, 44.74°, 59.28°, and 65.15° in the XRD pattern of ZnCo2O4(JCPDS No. 23-1390) belong to the (111), (220), (210), (311), (400), (511), and (440) crystal planes, indicating that ZnCo2O4 was synthesized by the microwave-assisted method. The characteristic diffraction peaks located at 20.9°, 29.7°, 33.3°, 36.6°, 47.9°, 52.8°, 55.1°, 57.4°, 61.7°, and 72.0° in the XRD spectrum of Ag3PO4catalyst correspond to the (110), (200), (210), (211), (310), (222), (320), (321), (400), and (421) crystallographic planes of Ag3PO4, which are consistent with the standard card of Ag3PO4 (JCPDS No. 70-0702). The characteristic diffraction peaks belonging to ZnCo2O4 in the XRD pattern of ZnCo2O4/Ag3PO4became more and more obvious with the increase in the amount of ZnCo2O4, which indicated that the ZnCo2O4 particles were successfully loaded onto the surface of Ag3PO4 to form the ZnCo2O4/Ag3PO4composite catalyst.