Perovskite LaNiO/AgPO heterojunction photocatalyst for the degradation of dyes.

Pristine lanthanum nickelate (LaNiO), silver phosphate (AgPO) and perovskite lanthanum nickelate silver phosphate composites (LaNiO/AgPO) were prepared using the facile hydrothermal method. Three composites were synthesized by varying the percentage of LaNiO in AgPO. The physical properties of as-prepared samples were studied by powder X-ray diffraction (pXRD), Fourier-transform infrared (FT-IR), Scanning electron microscopy (SEM) and Energy-dispersive X-ray (EDX). Among all synthesized photocatalysts, 5%LaNiO/AgPO composite has been proved to be an excellent visible light photocatalyst for the degradation of dyes i.e., rhodamine B (RhB) and methyl orange (MO). The photocatalytic activity and stability of AgPO were also enhanced by introducing LaNiO in AgPO heterojunction formation. Complete photodegradation of 50 mg/L of RhB and MO solutions using 25 mg of 5%LaNiO/AgPO photocatalyst was observed in just 20 min. Photodegradation of RhB and MO using 5%LaNiO/AgPO catalyst follows first-order kinetics with rate constants of 0.213 and 0.1804 min, respectively. Perovskite LaNiO/AgPO photocatalyst showed the highest stability up to five cycles. The photodegradation mechanism suggests that the holes ( ) and superoxide anion radicals plays a main role in the dye degradation of RhB and MO.