Controlled synthesis of silver/silver chloride composite crystals from [AgCl2]- complex and its photocatalysis properties on organic pollutants

The visible light catalyst has aroused scientific interest in order to address issues such as energy scarcity and pollution. Many parameters, such as morphology, composition, and structure, influence photocatalytic performance of semiconductors. Here, a new method of surfactant-assisted nanometer/micron size AgCl crystals with controllable morphology was attained and then formed Ag@AgCl crystals due to partial photoreduction of AgCl under the visible light. Temperature, humidity, and the quantity of surfactant (polyvinylpyrrolidone, PVP) were all controlled to produce different morphologies. It was found that the existence of PVP was the trigger for the synthesis of the linear AgCl crystals. The growth rate and time of AgCl crystals formation could be controlled by adjusting temperature and humidity conditions. The structure and constituents of the synthesized Ag@AgCl crystals were characterized by a polarizing microscope (POM), scanning electron microscope (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and photoluminescence spectroscopy (PL). The photocatalytic activity of catalyst was evaluated using methyl orange (MO) dye degradation studies. The results showed that too much or too little PVP did not favor the degradation of MO, and the pine needle-like crystals synthesized at a PVP / AgNO3 mass ratio of 5% showed the best photodegradation of MO with recyclability. Therefore, this study provides a new opportunity for the simple and controllable synthesis of Ag@AgCl crystals with rich morphologies. [Display omitted] •Synthesis of nano-micro AgCl crystals with controlled shape using surfactants.•Photoreduction of AgCl was carried out under visible light to obtain Ag@AgCl crystals.•Controlling reaction parameters resulted in granular and flower-like linear AgCl crystals.•Excellent photocatalysis of methyl orange under visible light.