Browsing by Subject "Visible photocatalysis"

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Open Access
Conscientious design of Zn-S/Ti-N layer by transformation of ZnTiO3 on electrospun ZnTiO3@TiO2 nanofibers: stability and reusable photocatalytic performance under visible irradiation
(American Chemical Society, 2018) Ranjith, K. S.; Uyar, Tamer
Herein, we report the rational design of Zn-S/Ti-N on TiO2 as a hierarchical nanoarchitecture from the ZnTiO3@TiO2 nanofibers (NFs) through electrospinning followed by a hydrothermal process using l-cysteine as an S/N source. Controlling the hydrothermal temperature, the hierarchical form of NFs exhibited highly efficient visible catalytic behavior for organic dye (i.e., Rhodamine B) degradation since S and N based surface function on the oxide surface resulted in unique interlayer induced strain coupled surface defects. The surface functionalization of the ZnTiO3 surface with S and N was solidly confirmed by X-ray photo-electrospectroscopy (XPS) and energy-dispersive X-ray (EDX) with elemental mapping results. Inducing the S/N functionality at higher hydrothermal temperature reverses the structural arrangement of ZnTiO3 favoring the interaction of S preferably with Zn and Ti with N for the formation of ZnS/TiN@TiO2 NFs. The tunable band function through the Zn-S/Ti-N cofunctionalization exhibited effective long-term catalytic performance under UV and visible irradiation with a degradation rate of 0.0362 and 0.0313 min-1, which is nearly 3.1 and 1.3 times higher than that of the ZnTiO3@TiO2 and ZnTiO3-S/N@TiO2 NFs, respectively. The catalysts are highly photoactive after multiple photocatalytic cycles with stable surface and structural features under visible irradiation. The study could provide new opportunities for designing hierarchical structures in ternary form of nanoscale architectures for effective visible photocatalytic activity. Copyright
Open Access
Multifunctional ZnO nanorod-reduced graphene oxide hybrids nanocomposites for effective water remediation: effective sunlight driven degradation of organic dyes and rapid heavy metal adsorption
(Elsevier, 2017-10) Ranjith, K. S.; Manivel, P.; Rajendrakumar, R. T.; Uyar, Tamer
We demonstrate the multi-functionality engineering on nanocomposite by combining one dimensional (1D) ZnO nanorod (NR) and two dimensional (2D) reduced graphene oxide (rGO) for efficient water remediation. Nano-engineered ZnO NR-rGO nanocomposites show efficient water remediation in terms of degradation of organic dyes and removal of heavy metal ions. Herein, we report on the fabrication of ZnO NR-rGO nanocomposite via a facile template-free hydrothermal route with an aim to improve the visible photocatalytic efficiency of the ZnO NR based nanocomposites. The structural and morphological features reveal that the rGO sheets are attached on the ZnO NRs and form a hybrid composite assembly. The surface enabled ZnO NR-rGO nanocomposites were used to degrade organic dye molecules (methylene blue (MB), methyl orange (MO) and rhodamine B (RhB)) under visible irradiation and adsorb Cu (II) and Co (II) ions from water through an adsorption process. The nanocomposite containing 7.5 wt% rGO and ZnO NRs shows a 4-fold enhancement in the visible photocatalytic activity and effective removal of Cu (II) and Co (II) ions from aqueous solution respectively. The photocatalytic performance is discussed in detail with respect to interaction between ZnO NRs and rGO sheets, light-harvesting properties of the nanocomposites. The effective experimental adsorption data also fit very well with the pseudo-second-order model which reveals the surface adsorption of metal ions. The results provide insight into a new method utilize for both visible photo degradation and adsorption for the removal of various wastewater pollutants. Construction of hybrid form of nanostructures delivers the effective catalytic properties with tunable functionalities for the water remediation.