Composites of BiVO4 and g-C3N4: Synthesis, Properties and Photocatalytic Decomposition of Azo Dye AO7 and Nitrous Oxide

• Published in: Journal of inorganic and organometallic polymers and materials 2019-07, Vol.29 (4), p.1219-1234
• Main Authors: Praus, Petr, Lang, Jaroslav, Martaus, Alexandr, Svoboda, Ladislav, Matějka, Vlastimil, Kormunda, Martin, Šihor, Marcel, Reli, Martin, Kočí, Kamila
• Format: Article
• Language: English
• Subjects: Bismuth oxides; Carbon nitride; Catalytic activity; Chemistry; Chemistry and Materials Science; Composite materials; Decomposition; Dyes; Heterojunctions; Hydroxyl radicals; Inorganic Chemistry; Melamine; Metal nitrides; Nitrous oxide; Orange II; Organic Chemistry; Photocatalysis; Photoelectrons; Photoluminescence; Polymer Sciences; Reflectance; Spectrum analysis; Vanadates; X ray photoelectron spectroscopy
• ISSN: 1574-1443; 1574-1451
• DOI: 10.1007/s10904-019-01085-4

The composites of BiVO 4 and g-C 3 N 4 (BiVO 4 /g-C 3 N 4 ) were synthesised by the calcination of a mixture of monoclinic BiVO 4 and bulk g-C 3 N 4 at 300 °C for 4 h. Both components were previously prepared by the precipitation of Bi(NO 3 ) 3 with NH 4 VO 3 and annealing of melamine. X-ray photoelectron spectroscopy (XPS) identified the presence of C–O and C=O bonds as well as metal nitrides which confirmed the formation of a heterojunction between BiVO 4 and g-C 3 N 4 . The heterojunction was also indicated by UV–Vis diffuse reflectance (DRS) and photoluminescence (PL) spectroscopy. The band gap energies were determined at 2.42–2.46 eV of BiVO 4 and 2.75–2.82 eV of bulk g-C 3 N 4 . The specific surface area was 23–28 m 2  g −1 of the composites and 6 m 2  g −1 and 35 m 2  g −1 of pure BiVO 4 and g-C 3 N 4 , respectively. The photocatalytic activity of the composites was investigated by the decomposition of Acid Orange 7 (AO7) and nitrous oxide. In case of AO7, the BiVO 4 /g-C 3 N 4 (1:3) composite was the most active one and the main role in the reaction was played by photoinduced holes forming hydroxyl radicals. At the decomposition of N 2 O, the most important species were the photoinduced electrons and the BiVO 4 /g-C 3 N 4 (1:1) composite was the most active photocatalyst.