Visible-Light-Induced Degradation of Rhodamine B by Nanosized Bi₂WO₆

Abstract

Visible-light-induced photodegradation of rhodamine B over nanosized Bi2WO6 has been observed. Bi2WO6 exhibited a high photoactivity to photodegrade rhodamine B in the central pH solution under visible irradiation (lambda > 420 nm). After five recycles for the photodegradation of rhodamine B, the catalyst did not exhibit any significant loss of activity, confirming the photocatalyst is essentially stable. The total organic carbon measurement displayed that a high degree of mineralization was achieved in the present photochemical system. The results of density functional theory calculation illuminated that the visible-light absorption band in the Bi2WO6 catalyst is attributed to the band transition from the hybrid orbitals of Bi6s and O2p to the W5d orbitals. The Bi2WO6-assisted photocatalytic degradation of rhodamine occurs via two competitive processes: a photocatalytic process and a photosensitized process. The transformation of rhodamine is mainly via the photocatalytic process. Kinetic studies by using electron spin resonance and the radical scavenger technologies suggest that *OH is not the dominant photooxidant. Direct hole transfers and O2*- could take part in Bi2WO6 photocatalysis. This study provided a possible treatment approach for organic pollutants by using visible light in aqueous ecosystems.

Facile Hydrothermal Preparation and Photocatalytic Activity of Bismuth Tungstate Polycrystalline Flake-ball Particles

“…2 It has been reported that Bi 2 WO 6 , which is a layered oxide and a member of cation-deficient Aurivillius phases, shows photocatalytic activity under visible-light irradiation for oxygen liberation from water and degradation of organic dye molecules in water. [3][4][5][6][7] We have developed, independently from the work by Huang's group, a facile hydrothermal reaction (HTR) of sodium tungstate (Na 2 WO 4 ) and bismuth nitrate (Bi(NO 3 ) 3 ) at 433 K for the preparation of micrometersized Bi 2 WO 6 polycrystalline particles with a hierarchical structure without using any structure-directing agents. The photocatalytic activities of the obtained hierarchicalstructured Bi 2 WO 6 particles were studied for several types of photocatalytic reactions.…”

DEGRADATION OF METHYLENE BLUE UNDER SOLAR LIGHT USING QUARTZ – Bi2WO6 NANOCOMPOSITES

“…Recently, it has also been reported that Bi 2 WO 6 is a good photocatalyst for water splitting and photodegradation of organic compounds under visible light irradiation [16,17]. Recently, Bi 2 WO 6 -based photocatalysts have been widely studied for their promising photocatalytic performance under visible-light-irradiation [18][19][20][21][22][23][24][25][26][27][28][29]. Unfortunately, the electron -hole recombination in Bi 2 WO 6 prohibits the desirable catalytic activity [30].…”

Preparation and Photocatalytic Activities of Fe/BiVO4 by Low-Temperature Solid State Method

“…Titanium dioxide (TiO 2 ) is an industrially important product, for example P25, however wide-band gap semiconductor always suffers from higher energy excited by UV-light [1][2][3][4], not adequately use sunlight. So face this trouble, except use of nanometer-structures and element doping [5], some new types photocatalyst had been utilized and investigated as BiVO 4 [6], BiFeO 3 [7], Bi 2 WO 6 [8], ZnWO 4 [9] and Cu 2 O [10]. Bismuth(III) metavanadate (BiVO 4 ) was narrow-band gap semiconductor materials on that presents interesting technological properties, especially photocatalytic activity and monoclinic BiVO 4 had better than tetragonal [11].…”