Perovskite LaNiO3/Ag3PO4 heterojunction photocatalyst for the degradation of dyes

Abstract

Pristine lanthanum nickelate (LaNiO3), silver phosphate (Ag3PO4) and perovskite lanthanum nickelate silver phosphate composites (LaNiO3/Ag3PO4) were prepared using the facile hydrothermal method. Three composites were synthesized by varying the percentage of LaNiO3 in Ag3PO4. 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%LaNiO3/Ag3PO4 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 Ag3PO4 were also enhanced by introducing LaNiO3 in Ag3PO4 heterojunction formation. Complete photodegradation of 50 mg/L of RhB and MO solutions using 25 mg of 5%LaNiO3/Ag3PO4 photocatalyst was observed in just 20 min. Photodegradation of RhB and MO using 5%LaNiO3/Ag3PO4 catalyst follows first-order kinetics with rate constants of 0.213 and 0.1804 min−1, respectively. Perovskite LaNiO3/Ag3PO4 photocatalyst showed the highest stability up to five cycles. The photodegradation mechanism suggests that the holes (h+) and superoxide anion radicals O2 •− plays a main role in the dye degradation of RhB and MO.

Modulation of the Internal Electric Field in Te-Doped Bi2MoO6 Nanosheets: Implication for the Photocatalytic Degradation of Rhodamine B and Photooxidation of Benzylamine

“… The higher adsorption capacity suggests a better interaction between the dye molecules and the catalyst, which usually leads to enhanced photodegradation performance. On the other hand, the catalytic performance decreases when there is excessive adsorption of dye on the surface of the catalyst, resulting in the obscuration of the photocatalytic active sites . As both the adsorption and surface area could play a role in photocatalytic activity, we additionally calculated the normalized apparent rate constant ( k app ′ ) where the rate constants are normalized by the surface area of each catalyst (Figure d).…”

“…On the other hand, the catalytic performance decreases when there is excessive adsorption of dye on the surface of the catalyst, resulting in the obscuration of the photocatalytic active sites. 49 As both the adsorption and surface area could play a role in photocatalytic activity, we additionally calculated the normalized apparent rate constant (k app ′ ) where the rate constants are normalized by the surface area of each catalyst (Figure 5d). The same trend is observed in k app ′ , suggesting that intrinsic properties of the catalysts play significantly more important role to the performance than the surface properties.…”