Visible Light Sensitive SnO2/ZnCo2O4 Material for the Photocatalytic Removal of Organic Pollutants in Water

Abstract

In this study, pure ZnCo2O4 and SnO2/ZnCo2O4 mix photocatalysts have been synthesized by the sol-gel process with three different SnO2 loading percentages (10, 20, and 30 wt %). Their photocatalytic activities were assessed on the degradation of organic pollutants in water under visible illumination. The structural, morphological, and optical properties were analyzed by X-ray diffraction (XRD), scanning electron microscopy, energy-dispersive X-ray (EDX), Fourier transform infrared (FTIR), nitrogen adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS), and UV–Visible diffuse reflectance measurements. The results have shown that the materials are composed of a crystalline ZnCo2O4 matrix with a decrease in crystallite size with the amount of SnO2. Weakly crystalline SnO2 is also observed for loaded samples. The specific surface area is modified with the loading ratio. The evaluation of the photoactivity of the samples under visible light for the degradation of p-nitrophenol has highlighted that all materials are highly photoactive under visible light thanks to heterojunction between the two oxides. An application test has been conducted on a dye, congo red, showing the same tendencies. An optimal amount of SnO2 loading is observed for the sample containing 20 wt % of SnO2. A comparison with commercial Evonik P25 showed that the materials developed in this work have five to six times better efficiency under visible light, leading to a promising photocatalyst material.

A novel n–p heterojunction Bi2S3/ZnCo2O4 photocatalyst for boosting visible-light-driven photocatalytic performance toward indigo carmine

“…The development of Bi 2 S 3 nanoparticles on the surface of ZC can interface in heterojunction which increases more photogenerated hole–electron pair, thereby enhancing the photocatalytic performance of 12.0Bi 2 S 3 /ZC. 26,27…”

“…24 Besides, ZnCo 2 O 4 is a promising candidate for fabricating an advanced p–n heterojunction in conjunction with other photocatalysts. 25 Some heterojunction structure was studied such as SnO 2 /ZnCo 2 O 4 , 26 ZnCo 2 O 4 /Bi 2 O 3 , 25 ZnO/ZnCo 2 O 4 , 27 CaFe 2 O 4 /ZnCo 2 O 4 , 28 BiVO 4 /ZnCo 2 O 4 in the photodegradation of dye molecules from aqueous solution .…”

Sonochemical synthesis of ZnCo2O4/Ag3PO4 heterojunction photocatalysts for the degradation of organic pollutants and pathogens: a combined experimental and computational study

“…Therefore, ZnCo 2 O 4 has been extensively used in lithium-ion batteries, energy storage, electrocatalysis and photocatalysis. 19–22 To improve the photocatalytic activity and photo-efficiency of ZnCo 2 O 4 , it is usually combined with other semiconductors such as Bi 2 O 3 , 22 SnO 2 , 23 ZnO, 24 TiO 2 , 25 and ZrO 2 . 26…”

ZnCo2O4/g-C3N4/Cu nanocomposite as a new efficient and recyclable heterogeneous photocatalyst with enhanced photocatalytic activity towards the metronidazole degradation under the solar light irradiation

“…25,26 It has found to be an ideal candidate for constructing an effective heterojunction with other semiconductors. 27 ZnCo2O4 with the large absorption range (200-800 nm), have particular optoelectronic properties that are beneficial for photocatalytic applications under solar irradiation. 28 Furthermore, owing to its special crystal structure, as well as the synergistic effects of its constituent metals, ZnCo2O4 shows superior electron conductivity and photo-electrochemical stability compared with single metal oxides ZnO and Co3O4.…”