Plasmon-Induced Photodegradation of Toxic Pollutants with Ag−AgI/Al₂O₃ under Visible-Light Irradiation

Abstract

A plasmonic photocatalyst Ag-AgI supported on mesoporous alumina (Ag-AgI/Al(2)O(3)) was prepared by deposition-precipitation and photoreduction methods. The catalyst showed high and stable photocatalytic activity for the degradation and mineralization of toxic persistent organic pollutants, as demonstrated with 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), and trichlorophenol (TCP) under visible light or simulated solar light irradiation. On the basis of electron spin resonance, cyclic voltammetry analyses under a variety of experimental conditions, two electron transfer processes were verified from the excited Ag NPs to AgI and from 2-CP to the Ag NPs, and the main active species of O(2)(*-) and excited h(+) on Ag NPs were involved in the photoreaction system of Ag-AgI/Al(2)O(3). A plasmon-induced photocatalytic mechanism was proposed. Accordingly, the plasmon-induced electron transfer processes elucidated the photostability of Ag-AgI/Al(2)O(3). This finding indicates that the high photosensitivity of noble metal NPs due to surface plasmon resonance could be applied toward the development of new plasmonic visible-light-sensitive photocatalysts and photovoltaic fuel cells.

Mechanism and experimental study on the photocatalytic performance of Ag/AgCl @ chiral TiO2 nanofibers photocatalyst: The impact of wastewater components

“…1). The rate of photocatalytic degradation of EE2 exhibited a slight variation in the presence of NaHCO 3 , but a contrast test indicated that this was due to an increase of pH [22], implying that h + have negligible contribution on the degradation of EE2. p-benzoquinone quencher had almost no influence on the photocatalytic degradation of EE2, indicating no ·O 2 -existed in the solution.…”

Synthesis and Characterization of Novel Plasmonic Ag/AgX-CNTs (X = Cl, Br, I) Nanocomposite Photocatalysts and Synergetic Degradation of Organic Pollutant under Visible Light

“…It has been reported that the Ag/AgI@Al 2 O 3 -supported plasmon-induced photocatalyst possesses much higher photocatalytic stability and activity than those of the bare Ag/AgI photocatalyst for the decomposition and mineralization of the toxic organics. 14 Another recent work report also indicated that a nanocomposites made of Ag/AgX loaded graphene oxide (GO) (Ag/AgX@GO) has significantly enhanced photocatalytic activity and stability as compared to those of bare Ag/AgX (X = Cl, Br) plasmonic photocatalysts. 16 These research findings imply that the photocatalytic activity as well as the stability of Ag/AgX can be significantly enhanced by loading onto a suitable supporting material.…”

Characterization and photostability of Cu2O–Ag–AgBr/Al2O3 for the degradation of toxic pollutants with visible-light irradiation

“…11). Under visible irradiation, the photocurrent increased and then decreased to a stable value, resulting in a peak at 0.21 V on Ag-AgBr/Al 2 O 3 , which was assigned to the oxidation of Ag NPs due to the plasmon-induced charge separation [14,18,27]. The peak with weaker intensity was also observed on Cu 2 O-Ag-AgBr/Al 2 O 3 photoanodes, indicating the lower amount Ag NPs were photocorrosioned in the presence of Cu 2 O.…”

“…In particularly, nanoparticles (NPs) of noble metals can strongly absorb visible light because of surface plasmon resonance, which greatly enhances the overall photocatalytic efficiency at the interface between the metal and the semiconductor [5][6][7][8][9][10][11]. Many plasmonic photocatalysts have been developed based on this phenomenon using a combination of Ag or Au NPs and semiconductor [3,[11][12][13][14][15]. The electron transfer was based on both photoexcitation of semiconductor and plasmon-excitations of noble metal NPs on the surface [14,16,17].…”

“…Many plasmonic photocatalysts have been developed based on this phenomenon using a combination of Ag or Au NPs and semiconductor [3,[11][12][13][14][15]. The electron transfer was based on both photoexcitation of semiconductor and plasmon-excitations of noble metal NPs on the surface [14,16,17]. The electron injection from surface plasmon resonant noble metal NPs into semiconductor and resultant oxidation of the noble metal NPs to ions, which is released into the aqueous, has been evidenced previously [18][19][20].…”