Synthesis of molybdenum–silver orthophosphate composites for the visible-light photocatalytic degradation of various dyestuff and phenol

Abstract

Molybdenum–silver orthophosphate (Mo–Ag3PO4) composites were synthesized through a simple co-precipitation method. Structure and optical characterization by X-ray diffraction, scanning electronic microscopy, transmission electronic microscopy, and UV–Vis diffused reflectance spectroscopy were used to elucidate morphology, structure, and topology of these newly developed materials. The photocatalytic performance of Mo–Ag3PO4 composites toward the degradation of Rhodamine B (RhB) was investigated, and the results proved that the degradation rate of RhB in Mo–Ag3PO4 composites (the mass ratio percentages of Mo2(OCOCH3)4 to AgNO3 were controlled as 1%, S2) was 0.2365 min−1, which was approximated to 103 and 1.2 times higher than that of Ag2O⋅MoO3 and bare Ag3PO4, respectively. In the stability study, Mo–Ag3PO4 composite (S2) exhibited no apparent loss of activity after four catalytic usages (92.4% degradation efficiency) compared with Ag3PO4 (45.5% degradation efficiency), which confirmed its stability. The feasibility of this Mo–Ag3PO4 composite (S2) was validated according to its ability to degrade RhB in environmental water samples, which also demonstrated its high photocatalytic activity. Hole and oxygen radicals are the two main reactive species generated photocatalytically in the mechanism from the light irradiation on Mo–Ag3PO4 composite (S2). The enhanced photocatalytic activity of Mo–Ag3PO4 composite (S2) could be attributed to a low electron–hole recombination rate, and highly efficient charge separation. Thus, a sustainable, low-power (merely 0.38 W/cm2) water treatment option by visible light was demonstrated.