Ghulam Yasin

Sapium sebiferum leaf extract mediated synthesis of palladium nanoparticles and in vitro investigation of their bacterial and photocatalytic activities

There is a growing need to introduce eco-friendly and sustainable procedures for the synthesis of metal nanoparticles that include a mild reaction conditions, simple reaction setup, use of nontoxic medium such as water and plant extract, cost effectiveness as well as greater efficiency for biomedical and catalytic applications. For this purpose, small and highly dispersed palladium nanoparticles (PdNPs) were prepared by eco-friendly and cost effective green method using water soluble leaf extract of Sapium sebiferum as a reducing and capping agent. The formation of PdNPs was optimized at various temperatures i.e. (30°C, 60°C and 90°C) and different leaves extract (5mL and 10mL) in order to control their size and shape. The results indicated that PdNPs synthesized at 10mL leaf extract concentration and 60°C temperature have small sized (5nm) and spherical shape. The nanoparticles formation, their dispersion, size and shape were confirmed by various characterization techniques i.e. UV-Vis spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), thermo gravimetric analysis (TGA) and Dynamic light scattering technique (DLS) analysis. The biologically synthesized PdNPs were tested for size dependent photo degradation of methylene blue and inactivation of bacteria. The PdNPs synthesized at optimized condition (10mL extract concentration and 60°C) have strong photo catalytic activity and reduced 90% methylene blue in 70min. The optimized PdNPs also showed strong bacterial inhibition against Staphylococcus aureus 29(±0.8mm), Bacillus subtilis 19(±0.6mm) and pseudomonas aeruginosa 11(±0.6mm). The results of this examination demonstrate effective applications of extremely active PdNPs.

Electrochemical deposition of nickel graphene composite coatings: effect of deposition temperature on its surface morphology and corrosion resistance

The present work describes the fabrication of Ni–graphene composite coatings on carbon steel at different deposition temperatures (15 °C, 30 °C, 45 °C and 60 °C, respectively) by an electrochemical codeposition method. The surface morphology, compositions, roughness and phase structures were examined by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM) and X-ray diffractometer (XRD), respectively. The polarization test and electrochemical impedance spectroscopy (EIS) were used to study the electrochemical properties of composite coatings. The results showed that the Ni–graphene composite coatings deposited at 45 °C exhibit coarser surface morphology with increased carbon content, refined grain sizes, high micro hardness and better corrosion resistance performance. At lower temperature relatively flat Ni–graphene composite coatings were obtained and the same characteristics of the coatings were investigated at higher than the peak value of the bath temperature. Thickness increased with the increasing of deposition temperature. The linear changes in composition and surface morphology of the Ni–graphene composite coatings were observed when the deposition temperature reached up to 45 °C.

Boron, zinc and microtone effects on growth, chlorophyll contents and yield attributes in rice ( Oryza sativa L.) cultivar

The micronutrient required in minute quantity and their deficiency leads to diminished growth and yield of crops. The effect of soil application of Zinc (Zn), Boron (B) and Microtone (MT) on growth, chlorophyll contents, mineral profile and yield components were investigated in rice at Chakkanwali Reclamation Research Station District, Gujranwala, Pakistan in the year 2011. Seven treatments which includes Zn 33% at 3 kg/acre, Zn 33% at 6 kg/acre, B 11.3% at 1.5 kg/acre, B 11.3% at 3 kg/acre, Zn + B at 3 + 1.5 kg/acre, Zn + B at 6 + 3 kg/acre and MT + Zn 6% + B + Fe + Mn + Cu 1% each at 500 ml/acre, and F0 considered as the control were used. The results reveal that foliar application of Zn and B (Zn + B at 6 + 3 kg/acre) were proved as the best balanced fertilizer dose for higher growth and yield response. The plant height, tiller/plant, panicle length, kernels/plant, filled kernel/plant, productive kernel, straw, paddy and biological yield increased up to 29.75, 38.40, 28.19, 25.81, 36.52, 38.52, 32.47, 38.27 and 31.79%, respectively. The chlorophyll contents, B and Zn contents in rice plant also increased significantly as compared to the control. However, the B, Zn and MT application reduced the amylase and protein contents of rice plant at all treatment levels.

Coupling of Bifunctional CoMn-Layered Double Hydroxide@Graphitic C3N4 Nanohybrids towards Efficient Photoelectrochemical Overall Water Splitting

The development of durable, low-cost, and efficient photo-/electrolysis for the oxygen and hydrogen evolution reactions (OER and HER) is important to fulfill increasing energy requirements. Herein, highly efficient and active photo-/electrochemical catalysts, that is, CoMn-LDH@g-C3 N4 hybrids, have been synthesized successfully through a facile in situ co-precipitation method at room temperature. The CoMn-LDH@g-C3 N4 composite exhibits an obvious OER electrocatalytic performance with a current density of 40 mA cm-2 at an overpotential of 350 mV for water oxidation, which is 2.5 times higher than pure CoMn-LDH nanosheets. For HER, CoMn-LDH@g-C3 N4 (η50 =-448 mV) requires a potential close to Pt/C (η50 =-416 mV) to reach a current density of 50 mA cm2 . Furthermore, under visible-light irradiation, the photocurrent density of the CoMn-LDH@g-C3 N4 composite is 0.227 mA cm-2 , which is 2.1 and 3.8 time higher than pristine CoMn-LDH (0.108 mA cm-2 ) and g-C3 N4 (0.061 mA cm-2 ), respectively. The CoMn-LDH@g-C3 N4 composite delivers a current density of 10 mA cm-2 at 1.56 V and 100 mA cm-2 at 1.82 V for the overall water-splitting reaction. Therefore, this work establishes the first example of pure CoMn-LDH and CoMn-LDH@g-C3 N4 hybrids as electrochemical and photoelectrochemical water-splitting systems for both OER and HER, which may open a pathway to develop and explore other LDH and g-C3 N4 nanosheets as efficient catalysts for renewable energy applications.

Effect of surfactant concentration in electrolyte on the fabrication and properties of nickel-graphene nanocomposite coating synthesized by electrochemical co-deposition

Long-time environmental protection of metallic materials is still required in the manufacturing and engineering applications. Nickel-graphene nanocomposite coatings have been prepared on carbon steel using sodium dodecyl sulfate (SDS) as a dispersant in the electrolyte by an electrochemical co-deposition technique. In this study, the effects of surfactants on graphene dispersion, carbon content in the coatings, surface morphology, microstructures, microhardness and corrosion resistance properties of the nanocomposite coatings are explored. The results indicate that the reasonably good graphene dispersion, coarser surface morphology and reduction in grain sizes are achieved upon increasing the surfactant concentration in the electrolyte. The surfactant also influences the preferred orientation of grains during electrodeposition; the (200) plane is the preferred orientation for the nanocomposite produced with SDS in the bath electrolyte. The microhardness, adhesive strength and corrosion performance of the nickel-graphene nanocomposite coatings are found to increase with the increasing concentration of sodium dodecyl sulfate in the deposition bath. Moreover, the influencing mechanism of surfactant concentration on the properties of nanocomposite coatings has been discussed.