Au-Pd bimetallic nanoparticles embedded highly porous Fenugreek polysaccharide based micro networks for catalytic applications

Mallikarjuna, K.,Bathula, Chinna,Dinneswara Reddy, G.,Shrestha, Nabeen K.,Kim, Haekyoung,Noh, Yong-Young Elsevier 2019 International journal of biological macromolecules Vol.126 No.-

<P><B>Abstract</B></P> <P>Currently, metallic nanoparticles possessing versatile heterogeneous catalytic functionality such as in hydrogenation, water splitting, hydrogen production and CO<SUB>2</SUB> reduction for global pollution remediation have been paid great attentions due to their high chemical stability, superior activity and unique electrical and optical properties. However, the gradual degradation of their catalytic activity on multiple usage limits the monometallic nanoparticles to industrial applications. Herein, we fabricated the highly porous fenugreek polysaccharide assisted green synthesis of AuPd nanostructures for heterogeneous catalytic hydrogenation of the industrial usable highly toxic 4-nitrophenol to the medicinally useful 4-aminophenol. The aqueous method developed in the present work is environmentally friendly, simple and low-cost procedure. The fabricated bimetallic porous AuPd nanostructures characterized using SEM, TEM, UV–Vis, XRD, XPS and FTIR analysis. The catalytic activity of the synthesized nanostructures was studied for the heterogeneous hydrogenation of 4-nitrophenol to 4-aminophenol in presence of NaBH<SUB>4</SUB>, and the catalytic kinetic for the hydrogenation was analyzed <I>via</I> an UV–Vis spectrometer.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Hydrogen Production from Water Splitting: Fabrication of ZnO Nanorod Decorated Cu NW Heterogeneous Hybrid Structures for Photocatalytic Applications

Mallikarjuna, K.,Kumar, M. Kotesh,Reddy, B. V. Subba,Kim, Haekyoung Springer-Verlag 2019 Journal of cluster science Vol.30 No.2

Synthesis and characterization of highly active Cu/Pd bimetallic nanostructures

Mallikarjuna, K.,Kim, Haekyoung Elsevier 2017 Colloids and surfaces. A, Physicochemical and engi Vol.535 No.-

<P><B>Abstract</B></P> <P>Researchers have tried to further advance the utilization of bimetallic nanoparticles in the field of catalysis due to their high stability, reusability, superior activity, and unique electronic and optical properties as compared with mono-metallic nanomaterials. Moreover, due to the lack of availability and economic viability of mono-metallic nanoparticles, it is necessary to produce highly active ultra-small bimetallic nanoparticles for industrial applications. Cu/Pd bimetallic nanoparticles are synthesized by using a mild hydrothermal one-pot method involving an aqueous solution with hexadecylamine as a capping agent for hydrogenation of aromatic nitro compounds. The synthesized bimetallic Cu/Pd nanoparticles form a cluster of 5±3nm bimetallic particles, and Cu/Pd clusters have been measured to perform the catalytic performance of hydrogenation of 4-nitrophenol, methylene blue, and methyl orange. Cu/Pd nanoparticles have been treated with lactic acid to remove the residual capping agent on the surface, which results in two times better catalytic relay effect between aromatic nitro compounds and NaBH<SUB>4</SUB> in aqueous media than Cu/Pd without lactic acid treatment.</P> <P><B>Graphical abstract</B></P> <P>The catalytic behavior of Cu/Pd bimetallic nanoparticles for nitro compounds.</P> <P>[DISPLAY OMISSION]</P>

Effect of Systemic Fungicide on Total Hemocyte Count and Hemolymph Biochemical Changes in Silkworm, Bombyx mori L., infected with Beau-veria bassiana

Mallikarjuna, M.,Nataraju, B.,Thiagarajan, V. Korean Society of Sericultural Science 2002 International Journal of Industrial Entomology Vol.5 No.2

Silkworm diseases are major constraint in silk cocoon production. Among silkworm diseases, white muscar-dine is highly contagious and most common in winter and rainy seasons. It is suggested that hemocytes involve in defense against invasion of Beauveria bassi-ana and systemic fungicide/chemicals prevent the proliferation of fungi in the hemolymph or preventing the growth of the fungi in the body cavity through enhancing the hemocyte mediated defense response. In the present study the influence of systemic fungicide on hematological changes in silkworms infected with Beauveria bassiana was reported. It is observed that the total hemocyte counts increased in the hemolymph up to 5 days post inoculation in systemic fungicide treated batches while in the inoculated control the increase was up to 3 days indicating the positive hemocyte mediated response in silkworm treated with systemic fungicide. After 2 days in the inoculated control as the multiplication and growth of mycelia increased, defense capacity of the silkworm was decreased. The biochemical changes were also observed in the hemolymph of silkworm infected with B. bassiana. In silkworm infected with Beauveria bassi-ana, the total protein content increased whereas total carbohydrate and total lipids decreased as the infection progresses. In the case of systemic fungicide treated batches the increase in total protein content was comparatively higher and decrease in total carbohydrate and lipids were comparatively lower than the inoculated control.

Sparsification of Digital Images Using Discrete Rajan Transform

Mallikarjuna, Kethepalli,Prasad, Kodati Satya,Subramanyam, M.V. Korea Information Processing Society 2016 Journal of information processing systems Vol.9 No.3

The exhaustive list of sparsification methods for a digital image suffers from achieving an adequate number of zero and near-zero coefficients. The method proposed in this paper, which is known as the Discrete Rajan Transform Sparsification, overcomes this inadequacy. An attempt has been made to compare the simulation results for benchmark images by various popular, existing techniques and analyzing from different aspects. With the help of Discrete Rajan Transform algorithm, both lossless and lossy sparse representations are obtained. We divided an image into $8{\times}8-sized$ blocks and applied the Discrete Rajan Transform algorithm to it to get a more sparsified spectrum. The image was reconstructed from the transformed output of the Discrete Rajan Transform algorithm with an acceptable peak signal-to-noise ratio. The performance of the Discrete Rajan Transform in providing sparsity was compared with the results provided by the Discrete Fourier Transform, Discrete Cosine Transform, and the Discrete Wavelet Transform by means of the Degree of Sparsity. The simulation results proved that the Discrete Rajan Transform provides better sparsification when compared to other methods.

Synthesis and Catalytic Activity of Alkylamine-Capped Ultra-small Palladium Nanoparticles for Organic Pollutant Degradation

Mallikarjuna, K.,Raju, B. Deva Prasad,Park, Sumi,Kim, Haekyoung Springer-Verlag 2017 Journal of cluster science Vol.28 No.5

<P>Over the past few decades, increasing attention has been focused on overcoming the scarcity of fresh water resources, with the rapid effluents of dyes from modern chemical industries causing issues in photosynthetic activity of aquatic organisms. In the process of recycling wastewater, the degradation of dye pollutants such as 4-nitrophenol, methylene blue, and methyl orange has become more crucial. Noble metal (silver, gold, palladium, and platinum) materials have significant potential applications in the areas of water purification, conversion of automobile exhaust emissions, and catalysis. Ultra-small alkylamine-capped palladium nanoparticles (APd NPs) with sizes below 10 nm are synthesized using hexadecylamine (HDA) as a stabilizing material, and HDA can prevent the irreversible aggregation of small-sized nanoparticles in solution-based reactions. The fabricated ultra-small APd NPs are investigated using UV-Vis, XRD, SEM, TEM, FTIR and TGA studies. In the presence of NaBH4 as a reducing agent, the APd NPs achieve high catalytic performance toward the degradation of dye pollutants such as 4-nitrophenol, methylene blue and methyl orange.</P>

Effect of fly ash and GGBS combination on mechanical and durability properties of GPC

Mallikarjuna Rao, Goriparthi,Gunneswara Rao, T.D. Techno-Press 2017 Advances in concrete construction Vol.5 No.4

Geopolymer is a sustainable concrete, replaces traditional cement concrete using alternative sustainable construction materials as binders and alkaline solution as alkaline activator. This paper presents the strength characteristics of geopolymer concrete (GPC) developed with fly ash and GGBS as binders, combined Sodium silicate ($Na_2SiO_3$) and Sodium Hydroxide (NaOH) solution as alkaline activators. The parameters considered in this research work are proportions of fly ash and GGBS (70-30 and 50-50), curing conditions (Outdoor curing and oven curing at $600^{\circ}C$ for 24 hours), two grades of concrete (GPC20 and GPC50). The mechanical properties such as compressive strength, split tensile strength and flexural strength along with durability characteristics were determined. For studying the durability characteristics of geopolymer concrete 5% $H_2SO_4$ solutions was used and the specimens were immersed up to an exposure period of 56 days. The main parameters considered in this study were Acid Mass Loss Factor (AMLF), Acid Strength Loss Factor (ASLF) and products of degradation. The results conclude that GPC with sufficient strength can be developed even under Outdoor curing using fly ash and GGBS combination i.e., without the need for any heat curing.

Synthesis of shape and size-dependent CuAg bimetallic dumbbell structures for organic pollutant hydrogenation

Mallikarjuna, K.,Kim, Haekyoung Elsevier 2018 Physica E, Low-dimensional systems & nanostructure Vol.102 No.-

<P><B>Abstract</B></P> <P>Combining silver and copper is a good way to decrease the cost of silver and the instability of copper. Bimetallic nanomaterials have emerged as effective catalysts with chemical and physical properties distinct from those of discrete metals. In this study, we develop a method for synthesis of CuAg bimetallic alloy nanostructures of different sizes and shapes without the need for laborious conditions or toxic agents. Therefore, it is a fast, effective, and green chemical method for synthesizing active bimetallic alloy catalysts. The prepared nanostructures were fundamentally analyzed by UV–Vis spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, field emission transmission electron microscopy, and X-ray photoelectron spectroscopy. The catalytic activities of the prepared CuAg bimetallic nanostructures were investigated for the hydrogenation of aromatic nitro compounds, such as 4-nitrophenol, methylene blue, and methyl orange in the presence of NaBH<SUB>4</SUB> in an aqueous medium.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of different sizes and shapes of CuAg bimetallic alloy nanostructures. </LI> <LI> The size and shape of the nanostructures were controlled by varying the Cu:Ag ratio. </LI> <LI> The catalytic performance of CuAg nanostructures was instigated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The catalytic performance of CuAg bimetallic alloy nanostructures for hydrogenation of aromatic nitro compounds to colorless intermediate amino compounds.</P> <P>[DISPLAY OMISSION]</P>

Green synthesis of palladium nanoparticles using fenugreek tea and their catalytic applications in organic reactions

Mallikarjuna, Koduru,Bathula, Chinna,Buruga, Kezia,Shrestha, Nabeen K.,Noh, Yong-Young,Kim, Haekyoung Elsevier 2017 Materials letters Vol.205 No.-

<P><B>Abstract</B></P> <P>In this communication, we present the fenugreek tea aided green synthesis of Pd nanoparticles (PdNPs@FT). The synthesized PdNPs were characterized by UV–Visible spectroscopy, scanning electron microscopy (SEM), small area electron diffraction (SAED), fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). FT-IR manifested that polyol and amide groups present in fenugreek may have participated in the synthesis of palladium nanoparticles. PdNPs@FT exhibited high catalytic activity towards hydrogenation of 4-nitrophenol to 4-aminophenol. PdNPs@FT catalyzed Suzuki–Miyaura coupling reaction between bromobenzene and phenyl boronic acid gave desired biphenyl in excellent yield.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of PdNPs@FT by the aid of fenugreek tea as green reducing agent is studied. </LI> <LI> Pd NPs@FT are found to be stabilized against agglomeration due to capping with tea extract. </LI> <LI> Pd NPs@FT demonstrating high catalytic activity towards hydrogenation and Suzuki–Miyaura coupling is observed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Simple synthesis of biogenic PdAg bimetallic nanostructures for an ultra-sensitive electrochemical sensor for sensitive determination of uric acid

Mallikarjuna, K.,Veera Manohara Reddy, Y.,Sravani, Bathinapatla,Madhavi, G.,Kim, Haekyoung,Agarwal, Shilpi,Gupta, Vinod Kumar Elsevier 2018 Journal of Electroanalytical Chemistry Vol.822 No.-

<P><B>Abstract</B></P> <P>Bimetallic nanomaterials have potential catalytic behaviour in hydrogenation, clean- energy production, catalysis and sensors due to their great stability, loftier activity unique electrical and chemical properties. Herein, we prepared PdAg bimetallic nanoparticles synthesized by using fungal extracted aqueous method, which is environmentally friendly cost-effective and simple procedure. The fabricated PdAg bimetallic nanoparticles were investigated by small area electron diffraction (SAED), transmission electron microscopy (TEM) X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) analysis. The electrochemical response of uric acid (UA) at Pd-Ag/CPE was studied in 0.1 M phosphate buffer solution at various pH, concentration and scan rate was investigated. Compare to Bare CPE, the PdAg nanocomposite modified electrode displayed the highest electrocatalytic activity for the detection of UA A linear response in the range of 4.69–273 nM with remarkable detection limit of 5.543 nM (C<SUB>DL</SUB> = 3ϭ/M) and quantification limit of 16.64 nM (C<SUB>QL</SUB> = 10ϭ/M) was obtained. The established nanoparticles (PdAg) embedded with carbon paste electrode (Pd-Ag/CPE) makes a good analytical tool for the sensing of UA in the biological and pharmaceutical samples.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pd-Ag bimetallic nanoparticles based electrochemical sensor was fabricated </LI> <LI> uric acid is determined at nanomolar levels </LI> <LI> The practical feasibility of the developed sensor was successfully was performed </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Electrochemical investigation of uric acid at biogenic PdAg bimetallic nanostructures modified carbon paste electrode.</P> <P>[DISPLAY OMISSION]</P>