Synthesis of Ag3PO4 microstructures with morphology-dependent optical and photocatalytic behaviors

The photodegradation activity and stability of silver orthophosphate (Ag 3 PO 4 ) photocatalysts have been greatly attributed to the morphology and exposed crystal facets. In this study, visible light-responsive Ag 3 PO 4 photocatalysts with fern-like, multipod-like and tetrapod-like morphologies were successfully synthesized using a facile soft-chemical technique. The morphology-controlled synthesis was conducted by changing tetrahydrofuran/water volumetric ratios in solutions containing orthophosphoric acid and silver nitrate precursors. The morphology effect on the physicochemical properties was systematically investigated using analytical methods including FESEM, EDS, XRD, FT-IR, Raman, UV–Vis DRS and PL. Ag 3 PO 4 microstructures were examined for their photocatalytic capabilities in the degradation of methylene blue (MB) under visible light irradiation. The assessment of the photocatalytic activity was performed through optimizing operational factors including irradiation time, pH, initial MB concentration and photocatalyst dosage. Fern-like Ag 3 PO 4 microstructures exhibited the highest photodegradation efficiency compared to other morphologies in which the degradation order followed a trend as fern-like Ag 3 PO 4 (85.91) > multipod-like Ag 3 PO 4 (74.72) > tetrapod-like Ag 3 PO 4 (62.92). The morphology-dependent photocatalytic performances of Ag 3 PO 4 microstructures were perfectly in agreement with the recombination rate of photoexcited electron–hole pairs and visible light adsorption capacity. Photodegradation process kinetics was explored through the Langmuir–Hinshelwood model, while the adsorption equilibrium was surveyed using Langmuir and Freundlich isotherms.