Enhanced Catalytic and Photocatalytic Degradation of Organic Pollutant Rhodamine‐B by LaMnO₃ Nanoparticles Synthesized by Non‐Aqueous Sol‐Gel Route

Abstract

The water crisis is one of the major problem of the 21 st century. This has led to the development of various techniques for water purification such as wastewater treatment. In this technique, coloring dyes are one of the most challenging materials to treat. Rhodamine-B (RhB) is one of the significant coloring agent and is very difficult to treat using conventional techniques. Here, the enhanced catalytic and photocatalytic degradation of RhB by LaMnO 3 nanoparticles is reported. The sol-gel route is used for the synthesis of LaMnO 3 nanoparticles, and structural, magnetic, optical and zeta potential studies are performed. X-ray diffraction analysis confirms the rhombohedral perovskite structure with R3c space group. The magnetic measurement at 5 K shows that saturation magnetization value increases with an increase in particle size. UV-vis absorption study of LaMnO 3 nanoparticles confirms the optical band gap decreases with increasing size. Zeta potential study of LaMnO 3 nanoparticles shows a negative charge on the surface. Degradation of organic pollutant RhB by nanoparticles of LaMnO 3 is performed under dark, followed by visible light irradiation. Under the dark, 90-92% of the RhB is degraded. Subsequently, upon visible light irradiation, it increased above 99%, confirming enhanced catalytic and photocatalytic activity of LaMnO 3 nanoparticles over RhB.

Response surface optimization and modeling of caffeine photocatalytic degradation using visible light responsive perovskite structured LaMnO3

“…The LaMnO3 perovskite photocatalyst was synthesized via the Pechini method, which utilizes metal nitrates with citric acid as the chelating agent [13]. The Pechini method is a twostage synthetic process that involves the formation of a complex between the metal ion precursors and citric acid.…”

“…Numerous semiconductor photocatalysts have been exploited for their potential in photodegradation applications [12]. Up until now, the most commonly used semiconductors in environmental remediation are the so-called wide-bandgap semiconductors such as TiO2 and ZnO [13]. However, it was realized that despite their merits such as; high photostability, low cost, and small environmental footprint [14].…”

“…For more efficient and low-cost utilization photodegradation schemes, the utilization of light in the visible region of the solar spectrum which constitutes about 40-50% of the entire solar spectrum must be considered [17,18]. Some of the methods that have been widely explored to improve the visible light responsiveness of wide-bandgap semiconductors photocatalyst include doping [19], dye sensitization [4,20], and surface property modification [13]. Despite the research efforts been exerted in trying to improve the visible responsiveness of wide-bandgap semiconductor photocatalyst [21].…”

Visible-Light-Driven AO7 Photocatalytic Degradation and Toxicity Removal at Bi-Doped SrTiO3

“…Perovskite-type compounds, such as halide perovskites, have been studied as promising photocatalysts for some applications such as CO 2 reduction under UV–visible radiation [ 9 ] and PET–RAFT polymerization under visible and near-infrared radiation [ 10 ], due to their superior properties. Other types, such as perovskite oxides, have shown to be more suitable than their halide counterparts for application as catalysts in the photocatalytic degradation of aqueous solutions of several compounds, including organic dyes, due to their higher water stability [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. These ceramic materials, with the general formula ABO 3 , are well known for their stable and flexible structure that allows the accommodation of several cationic combinations and consequent variety of properties.…”

Spray-Flame Synthesis of LaMnO3+δ Nanoparticles for Selective CO Oxidation (SELOX)

“…To produce rhombohedral/orthorhombic-LaMnO 3+δ nanoparticles, typically batch processes such as sol–gel or the citrate method are used. These processes count with a final calcination step involving temperatures usually higher than 600 °C , and long annealing periods of >2 h, making the formation of crystalline manganites with high surface area and thus low-size particles (ideally <20 nm) a challenge. As an alternative to common batch processes, the spray-flame synthesis (SFS) is a versatile, continuous, and scalable technique that allows to produce oxide materials with high crystallinity, high specific surface areas, and a controlled chemical and phase composition. , It is used for the synthesis of perovskites using either organometallic precursors (e.g., lanthanum­(III) 2-ethylhexanoate or lanthanum­(III) acetate, strontium­(II) acetate, iron­(II) naphthenate or iron­(II) acetate, cobalt­(II) acetylacetonate, and barium­(II) acetate) − or inorganic metal precursors (e.g., lanthanum­(III) nitrate, cobalt­(II) nitrate, and iron­(III) nitrate). , Regardless of the type of metal precursor, avoiding the formation of undesired secondary phases is always a challenge for the SFS of perovskites.…”