Enhanced solar photocatalytic activity of Er³⁺: YAlO₃-loaded BiPO₄ composite

Er³⁺:YAlO₃ loaded BiPO₄ were successfully synthesized by a simple heat treatment approach in order to enhance the photocatalytic efficiency of BiPO₄. Comparing with the simple substance of BiPO₄, the composite system showed the better efficiency on photodegradation of Methlyene Blue (MB) solution under a simulated solar light irradiation. The relationship between loading amount and degradation rate was also investigated. It is found that the optimal loading amount of Er³⁺:YAlO₃ is 7 wt%. The recycling test of selected sample was carried out to study the stability of the Er³⁺:YAlO₃ loaded BiPO₄ system. The composite materials were finally characterized by field-emission scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-visible diffuse reflectance spectroscopy (UV-vis DRS). Based on the findings a possible mechanism has been proposed. The existence of luminescence agent (Er³⁺-doped YAlO₃) and the occurrence of upconversion luminescence process have been related with the enhanced photodegradation of MB over composite system.