Photocatalytic activity of CaTaO2N nanocrystals obtained from a hydrothermally synthesized oxide precursor. (January 2016)

• Record Type: Journal Article
• Authors: Oehler, Florian; Naumann, Robert; Köferstein, Roberto; Hesse, Dietrich; Ebbinghaus, Stefan G.
• Is Part Of: Materials research bulletin. Volume 73(2016)
• Page Start: 276
• Page End: 283
• Publication Date: 2016-01
• Subjects: A. Oxides -- B. Solvothermal -- C. X-ray diffraction -- C. Electron microscopy -- D. Catalytic properties; Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2015.09.014
• Languages: English
• ISSNs: 0025-5408

Abstract

Graphical abstract: Highlights: CaTaO2 N was prepared by ammonolysis of a hydrothermally synthesized oxide precursor Obtained oxynitrides are single crystalline nanoparticles of roughly 45–67 nm The nano crystals show low strain, high thermal stability and bright colors Solution-based photocatalytic degradation of methyl orange was investigated Enhanced photocatalytic activity was found after loading with cobalt oxide Abstract: Highly crystalline CaTaO2 N nanoparticles possessing large specific surface areas were investigated as photocatalysts for the decomposition of methyl orange. Two different Ca2 Ta2 O7 precursors were synthesized by classical solid state synthesis and a hydrothermal soft-chemistry approach, respectively. In both cases, nitridation was carried out by thermal ammonolysis. The obtained CaTaO2 N samples were compared with respect to their optical, thermal and morphological properties as well as their photocatalytic activities. In particular, the influence of ammonolysis temperature on the photocatalytic properties was studied. Using hydrothermally synthesized Ca2 Ta2 O7, phase pure CaTaO2 N was obtained already at a relatively low ammonolysis temperature of 860 °C. Morphological investigations show that the CaTaO2 N samples from the hydrothermally synthesized precursor consist of single-crystalline particles of 45–70 nm diameter with high specific surface areas between 12 and 19 m 2 g −1, depending on ammonolysis temperature. A considerable photocatalytic activity for methyl orange degredation was found for the nanoscaled CaTaO2 N particles prepared at lower ammonolysis temperatures. Using CoO x as co-catalyst, a further strong enhancement of the methyl orange decomposition by a factor 5–10 was achieved.