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Visible-light responsive plasmonic Ag2 O/Ag/g-C 3N4 nanosheets (NS) were successfully prepared by a simple and green photodeposition method. The obtained composites were characterized by XRD, Fourier transform infrared, transmission electron microscopy, UV-vis, and the photoluminescence (PL) results indicated that the Ag2 O/Ag/g-C 3N4 NS composites showed better photoabsorption performance than g-C3 N4 due to the surface plasmon resonance effect of Ag nanoparticles. Meanwhile, the composite exhibited excellent photocatalytic activities, which was ;3.8 and ;3.0 times higher than those of bulk g-C3 N4 and pure g-C 3N4 NS, respectively. Moreover, the as-prepared composites showed a high structural stability in the photodegradation of Rhodamine B. A possible photocatalytic and charge separation mechanism was suggested based on the PL spectra and the active species trapping experiment.

I. INTRODUCTION

With increasing environmental problems and the energy crisis, photocatalytic degradation of organic pollutants or hydrogen production from water splitting over a semiconductor has attracted extensive attention.1–5 Taking into account that a substantial fraction (;48%) of the whole solar spectrum is visible light and the UV region accounts for only a small fraction (;4%) of the solar spectrum,6 the construction of suitable structures is of vital significance to extend absorption spectrum to visible light region. Therefore, many scientists devote their efforts to develop visible-light-responsive photocatalysts, and lots of semiconductor photocatalysts including WO3, CdS, graphene-based semiconductors have been reported. Two-dimensional (2D) layered nanosheets (NS), such as graphene, MoS2, CeO2, g-C3N4, possessed the ultra high specific surface area and strong quantum confinement of electrons.7–10 These ultrathin 2D nanomaterials display special optical, chemical, and electronic properties, which cannot be achieved by their bulk counterparts.11 Graphitic carbon nitride (g-C3N4) has recently emerged as a novel photocatalyst in photodegradation of organic pollutants under visible light.12–14 However, the catalytic activity of bulk g-C3N4 is still limited due to its low specific surface area and lack of active sites.15–17 Contributing Editor: Xiaobo Chen Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2016.234 J. Mater. Res., 2016

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Compared to bulk g-C3N4, 2D layered g-C3N4 NS exhibits highly improved electronic and optical features.12,18,19 These special properties make 2D layered g-C3N4 NS as a promising candidate for applications in solar photocatalysis for elimination of organic pollutants.19 Recently, many novel advanced photocatalysts have been designed on the basis of surface plasmon resonance (SPR) of metal nanoparticles such as Ag/AgBr,20,21 Ag/AgI/BiOI,22 Ag/g-C3N4,23 and so on.24–26 The reason is that the noble metal Ag particles can strongly absorb visible light owing to their localized SPR, resulting