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The nanoporous anodized aluminum oxide (AAO) templates were synthesized by two-step anodization in a solution of 0.5 M phosphoric acid at 60 V and temperature T ~ 0 °C. The CoMg nanowires were synthesized by template-based AC Electrodeposition technique at different voltages by AC source 13–17 V at room temperature. These CoMg nanowires were investigated via different characterization techniques such as scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM). The SEM result shows that nanowires have average diameter about 150 nm and length about 23 μm. The EDX reveals that nanowires only consisted of Mg and Co atoms, and atomic ratio of Mg/(Co + Mg) showed increasing tendency with deposition voltage which depicts that higher AC electrodeposition voltage is more suitable for Mg-rich deposition. The XRD results show that CoMg nanowires have hexagonal crystal structure with polycrystalline nature. The MH loops confirm that nanowires are soft ferromagnetic with uniaxial magnetic anisotropy. It is observed from angular dependence of coercivity that magnetization reversal mechanism occurs by a combination of curling and nucleation mode. The squareness (Mr/Ms) is found to be 0.24 along nanowires and 0.16 perpendicular to nanowire axis suggesting that easy magnetization direction lies along the nanowires. The effective anisotropy is observed along the nanowire axis due to dominance of shape anisotropy and suppression of dipole-dipole interactions among nanowires.

A simple approach to deposit metal chalcogenide-based quantum-dots on TiO2 (anatase) nanoparticles via pseudo-successive ionic layer adsorption and reaction (p-SILAR) was opted to design and investigate the corresponding photoactivity under visible light. We used TiO2/PbS and TiO2/CdS nanocomposites for photocatalysis after which we prepared solar paints from them to put side by side the resultant photovoltaic performance. We developed solar paint type quantum-dot-sensitized solar cells (QDSCs) from TiO2/PbS and TiO2/CdS nanocomposites to divulge electron-hole generation, electron-hole recombination, and resistance against photo-corrosion. TiO2/PbS exhibited higher electron-hole generation than TiO2/CdS owing to its efficient visible light harvesting capability which resulted in higher photocurrent density (JSC) and thus higher power conversion efficiency (PCE) for respective QDSC; however, it had inferior resistance against photo-corrosion. Additionally, the degradation of an azo-based dye (acid orange-56) reflected an effectual increase in the photocatalytic activity of anatase-TiO2 as a result of deposition of PbS and CdS QDs. TiO2/PbS performed better than TiO2/CdS as a photocatalyst under visible light irradiation.

Pseudo-successive ionic layer adsorption and reaction (p-SILAR) process was opted for deposition of PbS/CdS and CdS/PbS quantum-dots (QDs) on TiO2 to combine light absorbing tendency of PbS and CdS QDs which evolved significant photocatalytic behavior in TiO2 under visible light irradiation. It was shown that the resultant TiO2/PbS/CdS hierarchical nanocomposite exhibited better photo-electrochemical behavior than TiO2/CdS/PbS, ensuing ∼42% higher degradation of acid orange-56 than the latter and ∼65% higher than pristine TiO2. In addition, both nanocomposites resulted promising antibacterial activity against Escherichia coli (E. coli). Particularly TiO2/PbS/CdS showed much greater inhibition zone (∼14 mm) than TiO2 (∼8 mm).

Tellurium, sulfur and selenium elements are used to form the chalcogenide compounds by reaction of one or two of these elements with a metal. Such metal chalcogenides (e.g., PbS, CdS, SnS, SnSe and CuS etc.) are emerging as advanced energy materials owing to their efficient performance in various engineering applications including photocatalysis, solar cells, batteries and water splitting. In current study, S/Se based metal chalcogenide based compounds and composites (MCCs) were synthesized through facile fabrication techniques such as chemical bath deposition (CBD) and successive ion layer adsorption reaction (SILAR). We successfully, synthesized SnS, SnSe and CuS as well as their composites (e.g., SnSe/SnS), optimized the corresponding chemical recipes and characterized the compounds/composites using material characterization tools. Extensive field emission scanning electron microscopy (FE-SEM) coupled with energy dispersive spectroscopy (EDS) was used to reveal the morphology and the elemental composition respectively, while X-ray diffraction spectrometry, thermograviometery were employed to analyze the crystalline nature and thermal behavior of synthesized MCCs. All the MCCs were additionally characterized using particle size analysis. Furthermore, synthesized MCCs were employed to degrade the toxic organic dye and their appreciable performance was divulged in the light of mechanism of photocatalysis.

Simply by elevating the successive ionic layer adsorption and reaction temperature for ZnS deposition, we successfully demonstrated improved photostability of PbS-based quantum dot-sensitized solar cells (QDSCs) which was credited to efficient surface coverage of ZnS over PbS QDs and TiO2. Using open-circuit voltage decay and cyclic voltammetry techniques distinctly, it was affirmed that the back electron transfer at TiO2/PbS/electrolyte interface was reduced. Superior deposition of ZnS in terms of surface coverage not only exhibited increase in photocurrent density (from 20.7 mA/cm2 to 22.3 mA/cm2) and power conversion efficiency (from 3.1% to 3.4%), it also stabilized the normalized current significantly.