WO₃/Ag₂CO₃ Mixed Photocatalyst with Enhanced Photocatalytic Activity for Organic Dye Degradation

Abstract

The development of an efficient photocatalyst with superior activity under visible light has been regarded as a significant strategy for pollutant degradation and environmental remediation. Herein, a series of WO 3 /Ag 2 CO 3 mixed photocatalysts with different proportions were prepared by a simple mixing method and characterized by XRD, SEM, TEM, XPS, and DRS techniques. The photocatalytic performance of the WO 3 / Ag 2 CO 3 mixed photocatalyst was investigated by the degradation of rhodamine B (RhB) under visible light irradiation (λ > 400 nm). The photocatalytic efficiency of the mixed WO 3 /Ag 2 CO 3 photocatalyst was rapidly increased with the proportion of Ag 2 CO 3 up to 5%. The degradation percentage of RhB by WO 3 /Ag 2 CO 3 −5% reached 99.7% within 8 min. The pseudo-first-order reaction rate constant of WO 3 /Ag 2 CO 3 −5% (0.9591 min −1 ) was 118-and 14-fold higher than those of WO 3 (0.0081 min −1 ) and Ag 2 CO 3 (0.0663 min −1 ). The catalytic activities of the mixed photocatalysts are not only higher than those of the WO 3 and Ag 2 CO 3 but also higher than that of the WO 3 /Ag 2 CO 3 composite prepared by the precipitation method. The activity enhancement may be because of the easier separation of photogenerated electron−hole pairs. The photocatalytic mechanism was investigated by free radical capture performance and fluorescence measurement. It was found that light-induced holes (h + ) was the major active species and superoxide radicals (•O 2 − ) also played a certain role in photocatalytic degradation of RhB.

Experimental and computational study of metal oxide nanoparticles for the photocatalytic degradation of organic pollutants: a review

“…The main oxidative and reactive species were electrons and cOH radicals, holes were the minor oxidative species, and O 2 c − has considerable effects on the degradation of diclofenac. The cOH radicals can be obtained in two ways, as shown in eqn ( 11)- (13). In eqn (11), molecular O 2 reacts with the electrons (e − ) in the CB and resulted in O 2 c − .…”

“…Then, O 2 c − reacts with water molecules to produce cOH radical species, as shown in eqn (12). On the other hand, as shown in eqn (13), the h + can react with H 2 O on the surface of photocatalyst to produce cOH radical species.…”

“…Semiconducting metal oxides such as TiO 2 , ZnO, SnO 2 , Cu 2 O, Fe 2 O 3 , SrTiO 3 , zinc germanium oxide, bismuth oxides, copper oxides, and WO 3 have got much attention due to their ability in the degradation of various organic pollutants. 13,26 Their effective advantages are attributed to their large surface area, small size, optical and chemical properties, and electrical conductivity properties. 27 However, there are some shortcomings of semiconductor metal oxide photocatalysts such as a small range of the solar spectrum absorption abilities, wide bandgap, and fast recombination rates of photogenerated electrons and holes, which reduce their photocatalytic activities.…”

Enhanced Photocatalytic Activities of Ag2WO4 Modified Ag6Si2O7 through a Comprehensive p-n Heterojunction S-Scheme Process

“…Silver-based semiconductor materials have received significant attention for photocatalysis applications owing to their excellent bandgap and structural stability [11][12][13]. For instance, AgX-based (Cl, Br, and I) [14][15][16][17][18][19][20] semiconductors exhibit notable visible-sunlight harvesting and could be used to remove organic contaminants from water systems. Silver tungstate (Ag 2 WO 4 ) has also been extensively explored as a semiconductor photocatalyst for the decontamination of organic pollutants [21,22].…”

Synthesis of WO₃/Ag₃VO₄ photocatalyst with enhanced visible light efficiency photocatalysis

“…Therefore, various studies have been conducted to enhance photocatalytic activity of the WO3 photocatalysts. Many previous studies have been reported that combination of WO3 with another photocatalyst to establish a heterojunction system could enhance electron and hole separation efficiency as well as prevent the recombination of photo-excited electrons and holes leading to increase in its photocatalytic activity [4,9,10]. Due to its high stability and responsiveness to visible light, silver vanadate (Ag3VO4), another moderate band gap energy material that has attracted significant attention [11][12][13].…”