Synthesis and characterization of Ag+ and Zn2+ co-doped CaWO4 nanoparticles by a fast and facile sonochemical method

Author(s)

Andrade Neto, N. F. ^[1] ; Dias, B. P. ^[1] ; Tranquilin, R. L. ^[2] ; Longo, E. ^[2] ; Li, M. ^[3] ; Bomio, M. R. D. ^[1] ; Motta, V, F.

Affiliation

^[1] V, Fed Univ Rio Grande do Norte UFRN, Dept Mat Engn, LSQM Lab Chem Synth Mat, POB 1524, Natal, RN - Brazil

^[2] Univ Fed Sao Carlos, CDMF UFSCar, POB 676, BR-13565905 Sao Carlos, SP - Brazil

^[3] Univ Sao Paulo, IFSC, Av Trabalhador Sao Carlens 400, BR-13566590 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Journal of Alloys and Compounds; v. 823, MAY 15 2020.
• Web of Science Citations: 0

Abstract

In this work, Ag+ and Zn2+ co-doped CaWO4 nanoparticles were obtained by fast and facile sonochemical method. The nanoparticles were characterized by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), visible ultraviolet spectroscopy (UV-Vis) and photoluminescence property. The photocatalytic activity was studied against methylene blue (MB) dye under sunlight and CaWO4 powders were tested in 3 reuse cycles. The diffractograms indicate the non-formation of secondary phases and the Rietveld refinement estimated the crystallite sizes, being 27.38, 19.89, 18.70 and 16.39 nm for the pure, Ag, Zn and Ag:Zn samples, respectively. SEM and TEM images showed that the particles are agglomerated and have a mean diameter ranging from 16.76 (Ag:Zn) to 71.76 nm (pure). Defects generated by doping shift the gap band to higher energies and act to prevent electron/hole (e(-)/h(+)) pair recombination, reducing photoluminescence and favoring CaWO4 photocatalysis. Scavenger methodology indicated that h(+) is the main mechanism acting in photocatalysis, and the reuse tests indicated that the silver-doped sample, even with the better initial response, loses efficiency over the course of the cycle, while the co-doped sample maintains efficiency, and is therefore indicated for reuse photocatalysis applications in methylene blue dye degradation. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC