Muhammad Rafique

Nanostructured-based WO 3 photocatalysts: recent development, activity enhancement, perspectives and applications for wastewater treatment

The growth of highly ordered architectures of semiconductor metallic oxide photocatalyst has acknowledged great consideration due to natural growth along with exceptional morphology properties and potential application ways to resolve the problem of freshwater shortages in this world. Tungsten trioxide (WO3) is a well-known semiconductor photocatalyst due to its better response in solar spectrum, fine metal interactions, mechanical strength, high efficiency, harmlessness and cost-effectiveness. This review focuses on a precise and overall description of the recent literature relating pure and doped/composite WO3 catalyst, photocatalytic enhancement mechanism. Moreover, it will also elaborate the experimental conditions used photocatalyst synthesis processes, optimization of the parameters affecting the degradation efficiency of various dyes. Furthermore, strategies for improving photocatalytic activity of WO3 like metal doping, semiconductor coupling, metal sulfides and metal nitrides coupling are systematically summarized and highlighted. After this, future perspectives about advancement and applications are reviewed. It is expected that this review article could offer strategies for designing novel WO3-based photocatalysts which can have promising prospects of multifunctional applications to meet the imperative demands of highly efficient solar energy conversion.

An Optimal Au Grating Structure for Light Absorption in Amorphous Silicon Thin Film Solar Cell

Effect of different gold (Au) grating structures on light absorption in solar cell is investigated by finite elemental analysis using COMSOL multiphysics-RF module. The geometry of the solar cell consists of a 50-nm Au film on the substrate of amorphous silicon (a-Si). An optimum value of the slit width (w) of the Au grating has been obtained whereas periodicity of the grating structure remained the same. The periodicity in the grating device was chosen in such a way that the excitation of the surface plasmon polritons (SPPs) lies in the IR or NIR region where most of the spectrometers work well in practical life. Far-field transmission spectra were extracted from the grating device when illuminating with p-polarized light through the substrate side. Near-field plots of the Fano resonance (dip) associated with the excitation of the surface plasmon polritons (SPPs) were carefully examined to understand the underlying physics. It was deduced from the results that a grating device with slit width of 250–350xa0nm is the most efficient which reveals the fact that such device offers intermediate scattering from the grating structure and supports fundamental plasmonic mode. Hence, such devices absorb more light being most efficiently and find application in solar cell.

WO3 Nanostructures-Based Photocatalyst Approach Towards Degradation of RhB Dye

Tungsten trioxide (WO3) was prepared from the precursor sodium tungstate (Na2WO4·2H2O) in the presence HCl by cost-effective and eco-friendly facile hydrothermal method at different operating temperature 120, 150, 180 and 210xa0°C during autoclave reaction. Different properties like morphology, optical properties, structure tailoring and degradation rate of prepared samples were studied by characterization like SEM, EDX, XRD and photocatalysis respectively. The photocatalytic activity test was examined to degrade RhB dye under visible light irradiation. Experimental results revealed the higher photocatalytic performance at 180xa0°C. The better photocatalytic activity obtained due to extended region of visible light, lower particle size, better morphology and lower recombination rate.

Aquatic Biodegradation of Methylene Blue by Copper Oxide Nanoparticles Synthesized from Azadirachta indica Leaves Extract

The toxicity of methylene blue (MB) dye is increasing gradually in the environment due to human activities which can be reduced more effectively by green synthesis along with nanotechnology. A nanomaterial, copper oxide nanoparticles (CuONPs), is synthesized using leaves extract of Azadirachta indica (Neem) at room temperature. Surface plasmon resonance of biosynthesized material at 232–236xa0nm clue the formation of NPs of CuONPs. The average size of NPs is found as 21.6xa0nm using atomic force microscopy. The face centered cubic structure of the CuONPs was analyzed using X-ray diffraction analysis. Biosynthesized NPs effectively degraded MB dye under different reaction conditions like time of contact between CuONPs and MB, dose of the CuONPs, exposure of UV light and temperature of the reaction mixture. The degradation process was optimized on above conditions for the maximum removal of MB dye in wastewater.Graphical Abstract

A Review on Novel Eco-Friendly Green Approach to Synthesis TiO2 Nanoparticles Using Different Extracts

The inspiring applications of the metal oxide nanoparticles are capturing the interest of researchers worldwide. Different physical and chemical methods are being adapted to synthesize these nanoparticles. The green synthesis is a fruitful emerging process that is environment friendly and low-cost as well. During the last decade, a plenty of work on green synthesis of TiO2 nanoparticles had been practiced. In this review, a compact data on the green synthesis of TiO2 nanoparticles from the plant extracts is summarized. This review will also mention the amendable features for the qualitative and quantitative enhancement in the product and the reliable application perspectives.Graphical Abstract