Synthesis and Characterization of Ag-Ag2O/TiO2@polypyrrole Heterojunction for Enhanced Photocatalytic Degradation of Methylene Blue

Abstract

Hybrid multi-functional nanomaterials comprising two or more disparate materials have become a powerful approach to obtain advanced materials for environmental remediation applications. In this work, an Ag-Ag 2 O/TiO 2 @polypyrrole (Ag/TiO 2 @PPy) heterojunction has been synthesized by assembling a self-stabilized Ag-Ag 2 O (p type) semiconductor (denoted as Ag) and polypyrrole (π-conjugated polymer) on the surface of rutile TiO 2 (n type). Ag/TiO 2 @PPy was synthesized through simultaneous oxidation of pyrrole monomers and reduction of AgNO 3 in an aqueous solution containing well-dispersed TiO 2 particles. Thus synthesized Ag/TiO 2 @PPy was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and UV-Vis diffuse reflectance spectroscopy (UV-vis DSR). The photocatalytic activity of synthesized heterojunction was investigated for the decomposition of methylene blue (MB) dye under UV and visible light irradiation. The results revealed that π-conjugated p-n heterojunction formed in the case of Ag/TiO 2 @PPy significantly enhanced the photodecomposition of MB compared to the p-n type Ag/TiO 2 and TiO 2 @PPy (n-π) heterojunctions. A synergistic effect between Ag-Ag 2 O and PPy leads to higher photostability and a better electron/hole separation leads to an enhanced photocatalytic activity of Ag/TiO 2 @PPy under both UV and visible light irradiations.

Core-Shell Nanostructures of Graphene-Wrapped CdS Nanoparticles and TiO2 (CdS@G@TiO2): The Role of Graphene in Enhanced Photocatalytic H2 Generation

“…To understand the underlying reaction mechanism employing the CdS@xG@TiO2 samples, Mott-Schottky plots of pure CdS and pure TiO2 are measured to find the position of the conduction band potentials. Figure 7a,b represents the Mott-Schottky plots of pure CdS and pure TiO2 respectively confirming the n-type behavior of both semiconductors by exhibiting a positive slope of the plot [53,54]. The position of the conduction band of the n-type semiconductor is considered very close to the flat bandgap of the semiconductor, and hence the conduction band potential (ECB) of pure CdS and pure TiO2 is estimated to be −0.31 V and −0.05 V (vs. SHE, pH = 0) respectively as shown in Figure 7a,b.…”

Effective Electron Transfer Pathway of the Ternary TiO2/RGO/Ag Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

“…Combining TiO 2 with graphene could enhance the photocatalytic capacity, which facilitates the charge separation and transportation and suppresses the recombination of photogenerated electrons and holes [19][20][21]. Besides graphene, the decoration of noble metal Ag could enhance the photocatalytic activity of TiO 2 photocatalysts, due to the local surface plasmon resonance (LSPR) effect for optimizing the use of solar energy and improving the transfer efficiency of photogenerated carriers [13,[22][23][24][25][26].…”

Novel Synthesis of Plasmonic Ag/AgCl@TiO2 Continues Fibers with Enhanced Broadband Photocatalytic Performance

“…[9,10], and depositing with noble metals (Au and Ag, etc.) [11][12][13][14]. Ag 0 nanoparticles-modified TiO 2 exhibits excellent activity under visible light resulting from the surface plasmon resonance (SPR) [15,16], which is induced by the nano-size and morphology of Ag 0 [17,18].…”