Silver Doped Zinc Stannate (Ag-ZnSnO3) for the Photocatalytic Degradation of Caffeine under UV Irradiation

Abstract

Contaminants of emerging concerns (CECs) spread across a wide range of organic product compounds. As biorecalcitrants, their removal from conventional wastewater treatment systems remains a herculean task. To address this issue, heterogenous solar driven advanced oxidation process based-TiO2 and other semiconductor materials has been extensively studied for their abatement from wastewater sources. In this study, we have synthesized by hydrothermal assisted co-precipitation Ag doped ZnSnO3. Structural and morphological characterizations were performed via X-ray diffraction (XRD), Fourier transform infra-red (FTIR), N2 adsorption-desorption at 77 K by Brunauer-Emmet-Teller (BET) and Barrett, Joyner, and Halenda (BJH) methods, Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy coupled with Energy dispersive spectroscopy (SEM-EDS), and UV-visible absorption in Diffuse reflectance spectroscopy (UV-vis/DRS) mode. Crystallite size estimate for Ag-ZnSnO3 and undoped form was 19.4 and 29.3 nm, respectively, while respective TEM particle size estimate was 79.0 nm and 98.2 nm. BET surface area and total pore volume by BJH for Ag-ZnSnO3 were estimated with respective values of 17.2 m2/g and 0.05 cm3/g in comparison to 18.8 m2/g and 0.06 cm3/g for ZnSnO3. Derived energy band gap (Eg) values were 3.8 eV for Ag-ZnSnO3 and 4.2 eV for ZnSnO3. Photocatalytic performance of Ag-ZnSnO3 was tested towards caffeine achieving about 68% removal under (natural) unmodified pH = 6.50 and almost 100% removal at initial pH around 7.5 after 4 h irradiation. The effect of initial pH, catalyst dosage, pollutant concentration, charge scavengers, H2O2, contaminant inorganic ions (anions) as well as humic acid (HA) on the photocatalyst activity over caffeine degradation were assessed. In accordance with the probation test of the reactive species responsible for photocatalytic degradation process, a reaction mechanism was deduced.

Enhancing the TiO2-Ag Photocatalytic Efficiency by Acetone in the Dye Removal from Wastewater

“…Owing to their high potential applicability in wastewater treatment in a relatively cheap and green manner, the photocatalytic materials are now being intensively investigated [15][16][17]. Titanium dioxide (TiO 2 ) is the most used solid for photocatalytic reactions, due to its high photocatalytic efficiency, biological and chemical inertness, low toxicity and easy availability at an acceptable price [18].…”

In Situ Decoration of ZnSnO3 Nanosheets on the Surface of Hollow Zn2SnO4 Octahedrons for Enhanced Solar Energy Application

“…Synthesis of ternary metal oxides with controllable sizes and shapes has been an active research field in the past two decades, because of their size-and shape-dependent physical, chemical, optical, electronic, and catalytic properties [1][2][3]. In particular, the two zinc stannates, Zn 2 SnO 4 and ZnSnO 3 , have caused considerable attention due to their wide applications in dye-sensitized solar cells (DSSCs) [4,5], gas sensors [6,7], lithium-ion batteries [8,9], and photocatalysts [10,11]. Zn 2 SnO 4 and ZnSnO 3 are both photovoltaic and photocatalytic materials with band gaps of about 3.6 eV and 3.2 eV, and the Femi energy level of ZnSnO 3 is higher than that of Zn 2 SnO 4 [12,13].…”

Improved Capacitive Performance and Polarization Sustainability of Silver Stannate Nanoparticles: The Role of Carbon Nitride Incorporation

“…Zinc stannate-based materials exhibited remarkable performance in the fields of solar cells, sensors, catalysis, and battery applications. Silver-doped zinc stannate was synthesized using a hydrothermally assisted coprecipitation route, which exhibited an efficient photocatalytic degradation performance of caffeine under UV irradiation . It was reported that bismuth stannate-based films, on a glass substrate, displayed remarkable self-cleaning capability against organic dyes under visible light …”

“…Silver-doped zinc stannate was synthesized using a hydrothermally assisted coprecipitation route, which exhibited an efficient photocatalytic degradation performance of caffeine under UV irradiation. 10 It was reported that bismuth stannate-based films, on a glass substrate, displayed remarkable self-cleaning capability against organic dyes under visible light. 11 A series of metal stannate systems, as electrocatalysts, have been reported for the electrochemical reduction of carbon dioxide.…”