Study on structure and photocatalytic activity of Lanthanum-containing mixed metal oxide derived from ZnFe- Layered Double Hydroxides: An outstanding strategy for promoting visible light in indigo carmine photodegradation

Title : Study on structure and photocatalytic activity of Lanthanum-containing mixed metal oxide derived from ZnFe- Layered Double Hydroxides: An outstanding strategy for promoting visible light in indigo carmine photodegradation

Abstract:

With attempts to tune the photocatalytic activity of hydrotalcites catalysts and improving the photocatalytic performance via efficient separation of photoexcited electron-photogenerated hole. ZnFe_(1-x)La_x-LDH with variable Lanthanum cation contents (x = 0 to 5%) were prepared  by well-known co-precipitation method followed by heat treatment at 600 °C.  The synthesized photocatalysts were characterized by X-ray diffraction (XRD) and UV-visible diffuse reflectance spectroscopy (UV-Vis DRS). The analytical results showed that the crystallinity of the layered materials decreases as the La contents increases, probably due to the distortions introduced by the large difference in the ionic radii of the cations. UV-Vis DRS analysis demonstrated a decrease in the band gap of Lanthanum-substituted LDH compared to ZnFe-LDH. ZnFe_0.97La_0.03-600 was used as a photocatalyst to improve the degradation of IC under visible light in the presence of H₂O₂. In comparision, the kinetics of photo-discoloration is faster with ZnFe_0.97La_0.03-600 than with ZnFe-600. Indeed, a complete discoloration was obtained after 110 min and 240 min in the presence of ZnFe_0.97La_0.03-600 and ZnFe-600 respectively, the high photocatalytic activity of the sample was attributed to the addition of La(III). In addition, the study of the possible mechanism of photocatalytic degradation of IC by ZnFe_0.97La_0.03-600 showed that the HO^• and h⁺ species plays a major role. The material showed high stability after two regeneration cycles with good efficiency.

Keywords: LDH, co-precipitation, adsorption, ZnFe_0.97La_0.03-600, photocatalyst, visible light, indigo carmine dye.

Audience take-away:

• The public will be able to use what they have learned in the role of hydrotalcites containing lanthanum
• The detailed characterization of catalysts was performed.
• The development of systems capable of operating under visible or solar light, which is abundant and free.
• Proposed mechanism of mineralization of the dye.
• The catalyst can be used several times.

Biography:

Dr. Salima Bouteraa, A chemist researcher in inorganic materials chemistry at the Oran-MB University, Algeria with considerable industrial and analytical operations experience gained from working in the industrial and laboratorial sectors. Because her interest in environmental chemistry and chemistry of materials, she is doing her thesis in application of lamellar materials on wastewater depollution, specifically layered double hydroxides by adsorption, bi-adsorption and photodegradation of some dyes. She received her PhD degree in 2021 at the same institution. The scientific production during these years were 4 scientific peer-reviewed articles and 11 conferences.