Enhancement of Rhodamine B Degradation by Ag Nanoclusters-Loaded g-C₃N₄ Nanosheets.

Thi Le,Ngoc Lai,Van Nguyen,Danh Do,Thi Lam,Tuan Ngo,Thi Pham

doi:10.3390/polym10060633

Abstract

In this paper, silver (Ag) nanoclusters-loaded graphitic carbon nitride (g-C3N4) nanosheets are synthesized and their physical properties as well as photocatalytic activities are systematically investigated by different techniques. The existence of Ag atoms in the form of nanoclusters (NCs) rather than well-crystallized nanoparticles are evidenced by X-ray diffraction patterns, SEM images, and XPS spectra. The deposition of Ag nanoclusters on the surface of g-C3N4 nanosheets affect the crystal structure and slightly reduce the band gap energy of g-C3N4. The sharp decrease of photoluminescence intensity indicates that g-C3N4/Ag heterojunctions successfully prevent the recombination of photo-generated electrons and holes. The photocatalytic activities of as-synthesized photocatalysts are demonstrated through the degradation of rhodamine B (RhB) solutions under Xenon lamp irradiation. It is demonstrated that the photocatalytic activity depends strongly on the molar concentration of Ag+ in the starting solution. The g-C3N4/Ag heterojunctions prepared from 0.01 M of Ag+ starting solution exhibit the highest photocatalytic efficiency and allow 100% degradation of RhB after being exposed for 60 min under a Xenon lamp irradiation, which is four times faster than that of pure g-C3N4 nanosheets.

Highlights

Graphitic carbon nitride (g-C3 N4 ), an emerging graphene-like material, has received much attention for its use in numerous applications such as photocatalytic degradation of organic pollutants, conversion of carbon dioxide into hydrocarbons, production of hydrogen and oxygen, etc
We report a simple and environmental-friendly approach to synthesize g-C3 N4 /Ag heterojunctions in which the surface of g-C3 N4 nanosheets are decorated with Ag NCs to demonstrate the use of the material as an excellent candidate for photodegradation of rhodamine B (RhB)
It is obvious that pure g-C3 N4 and Ag cluster-loaded g-C3 N4 nanosheets synthesized with different Ag+ concentrations exhibited similar X-ray diffraction patterns

Summary

Introduction

Graphitic carbon nitride (g-C3 N4 ), an emerging graphene-like material, has received much attention for its use in numerous applications such as photocatalytic degradation of organic pollutants, conversion of carbon dioxide into hydrocarbons, production of hydrogen and oxygen, etc. Loading noble metal NPs such as Pt [15,16], Au [17,18], Pd [19,20], and Ag [21,22] on the surface of g-C3 N4 nanosheets have been reported as an efficient routine to enhance photocatalytic performance of g-C3 N4. This is because noble metal NPs can act as excellent electron acceptors [23], reducing the recombination rate of electron-hole pairs in g-C3 N4 nanosheets and improving visible-light absorbance [13]. When the particle size decreases to subnanometer scale, the NPs are just nanoclusters (NCs) of metal atoms, not crystalline, and they can exhibit interesting photocatalytic abilities [24,26]

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Conclusion