Synthesis of nanocrystalline eskolaite via grimaldiite
- PDF / 1,482,563 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 54 Downloads / 163 Views
ORIGINAL PAPER
Synthesis of nanocrystalline eskolaite via grimaldiite Marko Robić1 · Mira Ristić1 · Stjepko Krehula1 · Marijana Jurić1 · Svetozar Musić1,2 Received: 9 July 2020 / Accepted: 27 August 2020 © Institute of Chemistry, Slovak Academy of Sciences 2020
Abstract Grimaldiite (α-CrOOH) was precipitated hydrothermally from the C rCl3 aqueous solution in the presence of hexamethylenetetramine (HMTA). The crystallite size of grimaldiite samples was estimated to be ~ 2 nm. Eskolaite (α-Cr2O3) was produced by the calcination of grimaldiite at 500 and 700 °C. FE-SEM images showed amorphous-like aggregates of grimaldiite due to very fine particles (crystallites), whereas eskolaite was in the form of sphere-like nanoparticles. Synthesized grimaldiite and eskolaite were used in the investigation of rhodamine B (RhB) degradation. The significant degradation percentage of RhB obtained by grimaldiite was explained as catalytic effect (in dark) and photocatalytic contribution (with illumination). Keywords Grimaldiite · Eskolaite · HMTA · Nanocrystallinity · Rhodamine B
Introduction Synthetic eskolaite (α-Cr2O3) is an important technological material with many applications. It can be used as a green pigment, whereas very small C r2O3 particles can be used as a transparent colorant. Furthermore, there are applications of Cr2O3 in heterogeneous catalysis or as a possible sensing material. The Cr2O3 phase is important in many mixed metal oxide composites. Specific acido-basic surface properties make it an interesting adsorption material. Due to its high melting temperature (~ 2435 °C), C r2O3 is also an important refractory material. For these reasons, it is not surprising that many researchers investigated C r2O3 and CrOOH precursors from different aspects. In reference literature, different chemical and physical methods of Cr2O3 synthesis were applied. A simple method based on the hydrothermal treatment of the precipitate obtained by adding alkali to the Cr(III) salt solution was reported (Ratnasamy and Léonard 1972; Vayssieres and Manthiram 2003; Onjia et al. 2003; Kim et al. 2004; Yang
Deceased: Mira Ristić. * Svetozar Musić [email protected] 1
Division of Materials Chemistry, Rudjer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
Croatian Academy of Science and Arts, Zrinski trg 11, 10000 Zagreb, Croatia
2
et al. 2010). Thermal decomposition of chromium oxyhydroxide was also utilized to prepare Cr2O3 particles (Kittaka et al. 1985; Liang et al. 2014; Pardo et al. 2017). Tsuzuki and McCormick (2000) synthesized C r2O3 particles by mechanochemical processing of the N a2Cr2O7 + S mixture, followed by calcination at 520 °C. Bai et al. (2006) used the reductive conversion of K 2CrO4 with H 2 at 500 °C to prepare C r 2O 3 particles with a mean diameter ~ 0.3 μm. C r2O3 nanoparticles were prepared hydrothermally by reducing CrO3 with HCHO or C 2H5OH (Pei and Zhang 2008; Pei et al. 2009). Eskolaite (α-Cr2O3) was also synthesized using activated carbon as a reductant for Cr(VI)
Data Loading...
