Ceramics (Mar 2024)

Franklinite-Zincochromite-Gahnite Solid Solutions for Cool Red Ceramic Pigments with Visible Light Photocatalysis

  • Guillermo Monrós,
  • José A. Badenes,
  • Mario Llusar,
  • Carolina Delgado

DOI
https://doi.org/10.3390/ceramics7010022
Journal volume & issue
Vol. 7, no. 1
pp. 342 – 363

Abstract

Read online

Franklinite-zincochromite-gahnite solid solutions were prepared using ceramic or coprecipitation methods, and their pigmenting capacity as cool ceramic pigments in different glazes (double and single firing frits and porcelain frit) was studied. XRD, UV–Vis–NIR diffuse reflectance, CIEL*a*b* colour analysis, band gap measurements, and the photocatalytic degradation of Orange II were carried out to characterise the samples. The following criteria for high red colouring capacity and high NIR reflectance at the minimum Cr amount were found to be the optimal compositions for an intense reddish cool pigment: Zn(Fe1.8Cr0.2), Zn(Al1.5Cr0.5) and Zn(Al1.3Cr0.5Fe0.2)O4. All the powders showed a direct semiconductor behaviour, with a band gap of approximately 2 eV, which fell in the visible range (620 nm); the visible light photocatalysis of Orange II was moderate, but franklinite-zincochromite Zn(Fe1.8Cr0.2) stood out compared with silver orthophosphate.

Keywords