One-Step Hydrothermal Synthesis of Cu2ZnSnS4 Nanoparticles as an Efficient Visible Light Photocatalyst for the Degradation of Congo Red Azo Dye

Rodrigo Henríquez; Paula Salazar Nogales; Paula Grez Moreno; Eduardo Muñoz Cartagena; Patricio Leyton Bongiorno; Elena Navarrete-Astorga; Enrique A Dalchiele

doi:10.3390/nano13111731

One-Step Hydrothermal Synthesis of Cu₂ZnSnS₄ Nanoparticles as an Efficient Visible Light Photocatalyst for the Degradation of Congo Red Azo Dye

Nanomaterials (Basel). 2023 May 25;13(11):1731. doi: 10.3390/nano13111731.

Authors

Rodrigo Henríquez¹, Paula Salazar Nogales¹, Paula Grez Moreno¹, Eduardo Muñoz Cartagena¹, Patricio Leyton Bongiorno¹, Elena Navarrete-Astorga², Enrique A Dalchiele³

Affiliations

¹ Instituto de Química, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Valparaíso 2340000, Chile.
² Laboratorio de Materiales y Superficie, Departamento de Física Aplicada I, Universidad de Málaga, 29071 Málaga, Spain.
³ Instituto de Física, Facultad de Ingeniería, Herrera y Reissig 565, C.C. 30, Montevideo 11000, Uruguay.

Abstract

A hydrothermal method was successfully employed to synthesize kesterite Cu₂ZnSnS₄ (CZTS) nanoparticles. X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and optical ultraviolet-visible (UV-vis) spectroscopy were used for characterization of structural, chemical, morphological, and optical properties. XRD results confirmed that a nanocrystalline CZTS phase corresponding to the kesterite structure was formed. Raman analysis confirmed the existence of single pure phase CZTS. XPS results revealed the oxidation states as Cu⁺, Zn²⁺, Sn⁴⁺, and S^2-. FESEM and TEM micrograph images revealed the presence of nanoparticles with average sizes between 7 nm to 60 nm. The synthesized CZTS nanoparticles bandgap was found to be 1.5 eV which is optimal for solar photocatalytic degradation applications. The properties as a semiconductor material were evaluated through the Mott-Schottky analysis. The photocatalytic activity of CZTS has been investigated through photodegradation of Congo red azo dye solution under solar simulation light irradiation, proving to be an excellent photo-catalyst for CR where 90.2% degradation could be achieved in just 60 min. Furthermore, the prepared CZTS was reusable and can be repeatedly used to remove Congo red dye from aqueous solutions.

Keywords: CZTS; Congo red azo dye; hydrothermal; photocatalysis.

Grants and funding

This work was partially supported by CSIC (Comisión Sectorial de InvestigaciónCientífica) of the Universidad de la República, Montevideo, Uruguay, and PEDECIBA—Física, Uruguay. This work was also partially supported by MICINN of Spain through the research project PID2020-117832RB-100. Finally, this work also received support from Consolidated DI project nº 039.314/2022, PUCV, Chile.