CdS nanorod–MFe₂O₄ (M = Zn, Co and Ni) nanocomposites: a heterojunction synthesis strategy to mitigate environmental deterioration

Abstract

A facile strategy to encrust MFe 2 O 4 (M = Zn, Co and Ni) nanoparticles over CdS nanorods via two-step solvothermal method have been reported. The ferrite-CdS nanocomposites (NCs) were characterized using powder X-ray Diffraction (XRD) andFourier Transform Infrared (FT-IR) spectroscopy. A shifting in the peak corresponding to (311) plane confirmed the presence of different metal ion in the spinel ferrite lattice.However, no variation in the peak of CdS was observed which stipulate that phase and morphology of CdS nanorods remain unaltered after hydrothermal treatment. High Resolution Transmission Electron Microscopy (HR-TEM) analysis revealed the efficacious attachment of the nanoferrite on the CdS nanorods. Optical studies of the NCs samples provided the information about the fabrication of visible light responsive photocatalyst and covered the solar spectrum from 525 nm to 737 nm. On the basis of magnetic studies, CdS-CoFe 2 O 4 and CdS-NiFe 2 O 4 were found to be ferromagnetic in nature with saturation magnetization of 26.4 and 15.5 emu/g respectively. Interestingly, a transition from ferromagnetic to super-paramagnetic was observed for ZnFe 2 O 4 loaded CdS nanorods. The photo-catalytic activities of nanocomposites were studied by carrying out the photodegradation of rhodamine B and methylene blue dye under visible-light irradiation. Maximum activity was observed in case of CdS-ZnFe 2 O 4 nanocomposites. This behavior of saturation magnetization for CoFe 2 O 4 -CdS NCs is due to the strengthening of A-B interactions as the cobalt ion has a tendency to occupy octahedral B site. So, some of the Fe 3+ ions get transferred to the tetrahedral site and the magnetic moment of M B gets concerted. So, the saturation magnetization for the CoFe 2 O 4 -CdS NRs increased. However with the Zn 2+ ions substituent, A-B exchange interactions weaken as Zn 2+ ions have the tendency to occupy the tetrahedral A sites. So the magnetic moment of M A gets diluted. 29 Therefore, for ZnFe 2 O 4 -CdS NCs, the curve didn't get saturated, indicating the fabrication of super-paramagnetic nanocomposites with negligible coercivity and remanance. However NiFe 2 O 4 -CdS NCs displayed ferromagnetic behavior. This superparamagnetic behavior of ZnFe 2 O 4 -CdS NCs can be attributed to lower particle size and the presence of non-magnetic ions in the spinel ferrite structure, which would have led to single domains. 29 These results are corroborated by the presence of single domain structure in HR-TEM images (Fig. 3) A huge difference in magnetic parameters is also conspicuous from the hysteresis loops of the NCs. It is evident from the figure that the saturation magnetization value for the CdS-ZnFe 2 O 4 NCs is 4.0 emu/g. However for CdS-CoFe 2 O 4 NCs and CdS-NiFe 2 O 4 NCs saturation magnetization is 26.4 and 15.5 emu/g respectively. Similarly, a vast variation in the values of remanance and coercivity was observed. The coercivity for CdS-ZnFe 2 O 4 NCs was 8.5 Oe, which upsurged to 90 Oe and 377.2 Oe for CdS-NiFe 2 O 4 NCs and CdS-CoFe 2 O 4N...

Synthesis of Ultra‐Small Palladium Nanoparticles Deposited on CdS Nanorods by Pulsed Laser Ablation in Liquid: Role of Metal Nanocrystal Size in the Photocatalytic Hydrogen Production

“…In addition, the composites exhibit a slight blueshift of the primary peak of CdS, which corresponds to the band‐edge emission. The results show that the emission band at 534 nm is considerably stronger than that at 684 nm and that the CdS contains small defects . The emission intensities of the other nanocomposites are slightly decreased, which can be explained by the fact that the luminescence is quenched by the loading of Pd and PdPt nanoparticles on CdS as co‐catalysts, which serve as electron‐trapping sites.…”

“…The resultss how that the emission band at 534 nm is considerably strongert han that at 684 nm andt hat the CdS containss mall defects. [59] The emission intensities of the other nanocomposites are slightly decreased, which can be explained by the fact that the luminescence is quenched by the loading of Pd and PdPt nanoparticles on CdS as co-catalysts, which serve as electron-trapping sites. In addition, the co-catalysts can efficiently preventt he recombination of the photogenerated chargec arriers by acting as electron-trapping and reaction-active sites.…”

Construction of Isoenergetic Band Alignment between CdS QDs and CaFe2O4@ZnFe2O4 Heterojunction: A Promising Ternary Hybrid toward Norfloxacin Degradation and H2 Energy Production

“…The intense peak is observed due to excitonic fluorescence caused by radiative electron–hole recombination of the trapped electrons. The trapped charge carrier at the defect site of the CdS QDs and CdS QDs/CFO@ZFO heterojunctions indicates the weak transition bands . As we know, lower the peak intensity means delayed electron/hole recombination, and the greater the charge separation efficiency, and the better the photocatalytic activity.…”

“…The trapped charge carrier at the defect site of the CdS QDs and CdS QDs/CFO@ZFO heterojunctions indicates the weak transition bands. 41 As we know, lower the peak intensity means delayed electron/hole recombination, and the greater the charge separation efficiency, and the better the photocatalytic activity. From this observation, it is clear that the loading of CdS QDs in CFO@ZFO pn-heterojunctions facilitates the easy photogenerated electron−hole separation at the interface of the photocatalyst.…”

The synthesis of CoxNi1−xFe2O4/multi-walled carbon nanotube nanocomposites and their photocatalytic performance

“…[33][34][35][36] Therefore, CNTs have many unique mechanical, electrical and chemical properties due to their light weight and perfect hexagonal connection in the elds of composite materials, hydrogen storage, electronic devices, batteries, supercapacitors, eld-emission displays, quantum wire template electron guns, sensors and microscopic probes. [37][38][39][40][41] In recent years, in order to further expand the response range of catalysts in the solar spectrum, carbon-based semiconductor catalysts with excellent performance have been synthesized by combining carbon materials and semiconductors, resulting in fast electron conductivity, large specic surface area, high optical transparency, and high thermal conductivity. Carbon materials play a vital role in the utilization of solar energy.…”