AUTHOR=Ameen Shahzad , Murtaza Maida , Arshad Muhammad , Alhodaib Aiyeshah , Waseem Amir 

TITLE=Perovskite LaNiO3/Ag3PO4 heterojunction photocatalyst for the degradation of dyes

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.969698

DOI=10.3389/fchem.2022.969698

ISSN=2296-2646

ABSTRACT=<p>Pristine lanthanum nickelate (LaNiO<sub>3</sub>), silver phosphate (Ag<sub>3</sub>PO<sub>4</sub>) and perovskite lanthanum nickelate silver phosphate composites (LaNiO<sub>3</sub>/Ag<sub>3</sub>PO<sub>4</sub>) were prepared using the facile hydrothermal method. Three composites were synthesized by varying the percentage of LaNiO<sub>3</sub> in Ag<sub>3</sub>PO<sub>4</sub>. 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<sub>3</sub>/Ag<sub>3</sub>PO<sub>4</sub> 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 Ag<sub>3</sub>PO<sub>4</sub> were also enhanced by introducing LaNiO<sub>3</sub> in Ag<sub>3</sub>PO<sub>4</sub> heterojunction formation. Complete photodegradation of 50 mg/L of RhB and MO solutions using 25 mg of 5%LaNiO<sub>3</sub>/Ag<sub>3</sub>PO<sub>4</sub> photocatalyst was observed in just 20 min. Photodegradation of RhB and MO using 5%LaNiO<sub>3</sub>/Ag<sub>3</sub>PO<sub>4</sub> catalyst follows first-order kinetics with rate constants of 0.213 and 0.1804 min<sup>−1</sup>, respectively. Perovskite LaNiO<sub>3</sub>/Ag<sub>3</sub>PO<sub>4</sub> photocatalyst showed the highest stability up to five cycles. The photodegradation mechanism suggests that the holes (<bold><italic>h</italic></bold><sup>+</sup>) and superoxide anion radicals <inline-formula id="inf1"><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mfenced open="" close=")" separators="|"><mml:mrow><mml:msubsup><mml:mrow><mml:mfenced open="(" close="" separators="|"><mml:mrow><mml:mi mathvariant="bold-italic">O</mml:mi></mml:mrow></mml:mfenced></mml:mrow><mml:mn mathvariant="bold">2</mml:mn><mml:mrow><mml:mtext> </mml:mtext><mml:mo>•</mml:mo><mml:mo>−</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:mfenced></mml:mrow></mml:math></inline-formula> plays a main role in the dye degradation of RhB and MO.</p>