Allium sativum extract derived silver nanoparticles (AS‐AgNPs, 18 nm) and its Metformin conjugate (AS‐AgNP‐Met, 21 nm) is tested against multi drug‐resistant (MDR) Staphylococcus aureus and Escherichia coli and compared to establish the enhanced synergy of AS‐AgNP‐Met. The plasmon band of spherical AS‐AgNPs is observed at 421 nm and zeta potential, −34.5 mV at pH 5.6. The spherical As‐AgNP‐Met shows zeta potential, −26.9 mV. The MIC, 5–15 µg/mL; MBC, 15–30 µg/mL and zone of inhibition (ZOI) 13–16 mm at MIC dose for AS‐AgNPs while the AS‐AgNP‐Met shows MIC, 2.5‐5 µg/mL; MBC, 10–20 µg/mL and ZOI, 17–19 mm. The biofilm formation in MDR E. coli and MDR S. aureus post AS‐AgNPs treatment at MIC diminished to 55% and 78% respectively, while post AS‐AgNP‐Met treatment at MIC, the reduction was 50% and 19% respectively. The cytotoxicity is determined by MTT assay. The FE‐SEM of AS‐AgNP‐Met treated isolates exhibited pronounced membrane disintegration compared to AS‐AgNP. A molecular docking analysis shows the strong binding of AS‐AgNP/AS‐AgNP‐Met with the DHPS (dihydropteroate synthase) protein. The biogenic AS‐AgNP has been conjugated with Metformin (AS‐AgNP‐Met) and the combined drug is a more effective antimicrobial agent in treating MDR strains than that of pristine AS‐AgNPs.

Thermal polymerization of urea and thiourea under closed conditions at 370 degrees C have been independently carried out and the derived samples were subjected to detailed characterization techniques that showed varied chemical compositions as well as distribution of functional groups despite the same C/N atomic ratio. The detailed optical, physicochemical and morphological characterizations from FTIR, RAMAN, XRD, TGA, XPS, solid-state & solution-state NMR, solid state UV-visible absorption, PL, BET, FESEM, TEM and SAED revealed that urea derived U370 sample with 2D flakes-like morphology closely resembles melem-cyanuric acid complex/adduct while thiourea derived T370 sample having flat ribbon-like structure can be intimately related with oligomeric melem (s-heptazines) hydrate respectively. Solution state UV-visible absorption spectroscopy, Zeta potential and Dynamic Light Scattering (DLS) aided size distribution studies were also conducted in aqueous media with varying pH to comprehend the character of chemical functionalities and nature of prevailing interactions in acid, neutral and alkaline electrolytes which were further be correlated with their photoelectrochemical responses. Their comparative electrochemical studies were conducted in aid with CV, GCD and EIS studies both under dark as well as in presence of different and wide range light sources in acid, neutral and basic media correspondingly to design low costing, eco-friendly, smart materials for light-driven supercapacitive devices. Results revealed T370 sample with better photoelectrochemical performance in terms of higher normalized areal capacitance, better rate capacity as well as improved cyclic stability than U370 sample in aqueous alkaline electrolyte. Thus, this communication outlines a novel approach for significantly upgrading the supercapacitive responses of materials using the simple aid of electromagnetic radiation, thereby opening up new roadways in the emerging field of photoelectrochemical charge storage and conversion technology.

Nanoparticles of n-AgBi3S5, n-Bi2S3, and n-n-AgBi3S5-Bi2S3 nanocomposite were synthesized by a facile one-pot hot chemical (90 °C) method using ethylene glycol as a medium without further calcination. The nanocomposite on exposure to natural sunlight exhibits significant and synergistic photocatalytic activity towards degradation of pollutant dye Rhodamine-B (Rh-B) in aqueous solution. The as-synthesized monoclinic AgBi3S5, orthorhombic Bi2S3, and their nanocomposite were identified and characterized by various spectroscopic, diffraction (XRD), and microscopic techniques. The UV-visible spectroscopic study reveals significant absorption of visible light and narrow band gaps/eV: 2.8 and 1.9 for synthesized Bi2S3 and AgBi3S5 respectively. The spectroscopically evaluated maximum % of degradation of Rh-B (99.9) and related high-rate constant (0.059 min–1) were achieved within 25 min with 0.7 g/L AgBi3S5-Bi2S3 nanocomposite at pH 3. The radical trapping experiments reveal that both •O2– and •OH are almost equally involved in the degradation, while hole, h+ is the main initiator of the degradation as usual. Studies of the products of degradation reveal both de-ethylation and ring breaking of Rh-B, indicating simultaneous absorption of sunlight by it and the catalyst. The very high efficiency and synergistic effect of the nanocomposite might be due to either/both Z scheme/S scheme charge separation. The 95% retention of the photocatalytic activity by the 5th time used catalyst AgBi3S5-Bi2S3 signifies its superiority by auto surface improvement during a reaction.

A facile fast synthetic route is designed to prepare a versatile nano-electrocatalyst AgBi3S5 (ABS) for the generation of green fuel, H-2, via water electrolysis. The XRD pattern confirms the major formation of monoclinic phase AgBi3S5 (ABS) along with binary phase Ag2S (AS) and Bi2S3 (BS). Another variant CuBiS2(CBS) nanoparticle is synthesized to compare the electrochemical result with the unique sustainable as-synthesized nanoparticles of the ABS compound. Microscopy (HR-TEM) and spectroscopy (FTIR) studies provide confirmational evidence of the syntheses of ABS, AS, BS, and CBS, respectively, while an XPS study confirms the presence of Ag, Bi, and S in ABS. From the electrochemical analysis, it is evident that ABS shows a lower overpotential value of 47 mV compared to those of other variants (AS - 93 mV, BS - 191 mV, CBS - 603 mV) and lower Tafel slope values (mV dec(-1)) (75.99) than the others (AS - 101.54, BS - 120.29, CBS - 265.2), which are key aspects in analyzing the catalytic activity performance of the catalyst. It is also proved that the rate-determining step of the reaction proceeds through the Volmer-Heyrovsky step. A lower EIS value of 9.84 Omega with a higher active surface area value of 0.092 cm(2) for ABS indicate superior and effective electron charge transfer kinetics on the electrode-electrolyte interface and elevated activity compared to the other electrocatalysts (AS - 15.24 Omega and 0.035 cm(2), BS - 16.01 Omega and 0.014 cm(2), and CBS - 19 Omega and 0.005 cm(2)). On top of that, an acceleration degradation (AD) study before and after analysis performed at 100 mVs(-1) for 500 cycles in acidic solution discloses the fact when comparing the two LSV curves there is a small hike (8 mV at 10 mA cm(-2)), suggesting higher stability and low catalyst degradation for ABS. Chronoamperometric studies with a fixed applied potential of -0.065 V vs. RHE also reveal that the catalyst (ABS) shows retention of activity after a 72 hour long-term process in a cathodic environment.

Among the transition metals copper is one of the cheapest earth- abandoned elements which can enhance electrocatalytic activity. The Cu -based catalysts are superior for catalytic performance and stability in alkaline media for oxygen evolution reaction (OER) and exhibit high activity in acidic media for hydrogen evolution reaction (HER).Synthesized CuSe nanoparticle is found as the most efficient bifunctional electrocatalyst among the synthesized Cu chalcogenides for water splitting reaction. Electrocatalytic performance for water oxidation was investigated in alkaline solution1(M) KOH for OER and 0.5 (M) H2SO4 for HER. To achieve 10 mA/cm2, it was observed an over potential (mV) of 343 for OER and 126 for HER, which are much smaller than these of CuS (385,320) and CuO (410, 345) studied. In this article, we have elucidated some essential criteria need to be specified to evaluate the water splitting performance including onset potential, overpotential, Tafel slope, turnover frequency (TOF), and stability of the copper chalcogenide nanoparticles.

In this work, we have synthesized NiO, NiS and NiSe nanoparticles by similar hydrothermal method and the electrocatalytic activities of the graphite carbon-supported synthesized materials have been compared in reference to hydrogen and oxygen evolution reactions (HER and OER) in aqueous acidic and alkaline media respectively. The as-synthesized nanoparticles have been characterized by using powder X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopic studies. The best electrocatalyst, NiSe provides a current density of 10 mA cm−2 at 259 mV overpotential for OER in 1.0 M KOH, which is superior to that of the state-of-the-art catalyst RuO2 in the same environment. For HER the best electrocatalyst, NiSe provides a current density of 10 mA cm−2 at 49.5 mV overpotential in 0.5 M H2SO4, which is again superior to Pt wire electrode. The order of electrocatalytic activity in both HER and OER has been found to follow the sequence: NiSe > NiS > NiO under the same electrochemical conditions, as have been evident from cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopic studies. While the electrochemical surface area is increased by 16.4 % and 37.3 % on changing the electrocatalyst from NiO to NiS and NiSe respectively, the chronoamperometric current densities are increased by 429 % and 635 % at 0.8 V for OER and 548 % and 9733 % at −0.4V for HER on changing the same materials. Thus, the enhancement in catalytic activity hangs mainly on the material characteristics besides the morphological improvement.

Pt-based nanocomposites such as Pt- metal oxide framework have been widely used as electro catalysts for direct methanol fuel cell (DMFC) due to their significant catalytic activity and stability. In this study, Pt-NiO encapsulated with reduced graphene oxide (rGO) nanosheet is prepared by making a thin film of GO over deposited Pt-NiO on Indium tin oxide support, followed by facile electrochemical reduction technique. As-synthesized materials are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The electrocatalytic performance is investigated by cyclic voltammetry (CV), chronoamperometry and impedance spectroscopy. These results indicate that Pt-NiO/rGO ternary phase catalyst junction exhibits significant CV peak current density (669 mA mg(-1) of Pt) which is 2.9 and 1.7 times higher than that of fabricated Pt-NiO and commercial Pt(10 mass% )-XC72 respectively. The electrode also possesses excellent stable catalytic activity than Pt-NiO. The charge transfer conductance of Pt-NiO based electrode is improved 17 times and the electrochemical surface area is increased by ca. 2 times by incorporation of overhead rGO nanosheet. These results imply that Pt-NiO/rGO nanocomposite could be a better electrocatalyst for DMFCs application.

Conductivity and transport properties of a cost-effective and environment friendly chitosan based solid biopolymer electrolytes which form mechanically robust thick film, have been reported here. A maximum ionic conductivity of ∼ 10 -4 S/cm has been achieved by optimizing the concentrations of the salt (LiClO 4 ) and the plasticizer (EC) in the biopolymer electrolyte. Ion transport properties of the biopolymer electrolytes are studied from Raman spectroscopy. A dye-sensitized solar cell (DSSC), with a sandwich structure, is fabricated with chemically synthesized ZnO (∼ 60 nm) as the nanoporous semiconductor material coated with Rose Bengal dye as a photosensitizer, the chitosan biopolymer as electrolyte and platinum as counter electrode. Linear Sweep Voltammetry analysis of the DSSCs illustrates the photovoltaic performance of these cells. Without any external addition of redox couple in the biopolymer electrolytic system, a maximum short-circuit current density of J SC = 0.556 mA/cm 2 and open-circuit voltage V oc = 0.605 V with power conversion efficiency 0.051 % is achieved by the DSSC.

Recently, photo-electrooxidation of fuel using a noble metal-semiconductor junction has been one of the most promising approaches in fuel cell systems. Herein, we report the development of a Pd-supported Bi2MoO6-Bi2O2CO3-CuO novel ternary heterojunction for ethanol oxidation in alkali in the presence and absence of visible light. Various spectroscopic and microscopic characterization techniques confirm strong coupling between palladium nanoparticles and Bi2MoO6-Bi2O2CO3-CuO ternary heterojunction supports. The photo-electrocatalytic efficacy of the synthesized catalysts was inspected by cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The CV study reveals that the forward peak current density (in mA mg-1 of Pd) of the synthesized quaternary heterojunction was about 1482.5, which is 2.4, 4, and 4.6 times higher than that of Pd/CuO (608.3), Pd/Bi2MoO6-Bi2O2CO3 (368.3), and similarly synthesized Pd catalyst (321.5) under visible light radiation. The best heterojunction catalyst shows 2.21-fold higher peak current density in visible light compared to that in dark. CA study reveals that after operation for 6000 s, the current density of the quaternary electrode is 1.5 and 3.4 times greater than that of Pd/CuO and Pd/C catalysts, respectively. The greater photocurrent response, lower photoluminescence (PL) emission intensity, and smaller semicircle arc in the Nyquist plot of the quaternary catalyst demonstrate the efficient segregation and higher charge transfer conductance of photogenerated charges to facilitate the photo-electrooxidation process of ethanol. The stability test shows that the quaternary catalyst loses only 9.8 and 7.7% of its maximum current density after 500 cycles of CV operation in the dark and light, respectively, indicating that light energy is more beneficial in establishing high stability. The dramatic enhancement of the photo-electrocatalytic activity of the quaternary electrode is owing to the lower band gap, high ECSA, enhanced charge separation of photogenerated carriers (e--h+), and all cocatalytic support of Bi2MoO6, Bi2O2CO3, and CuO in Pd/ Bi2MoO6-Bi2O2CO3-CuO under visible light radiation. The morphology and structure of the used quaternary catalyst are tested using FESEM and PXRD. Finally, ex situ FTIR spectroscopy and HPLC techniques help understand the ethanol electrooxidation reaction mechanism.

Ever increasing use of conventional energy and demand of clean renewable energy inspire many researchers to produce effective systems for hydrogen generation. Herein we report two mononuclear complexes, [NiL] (Complex 1) and [CuL] (Complex 2), where H2L is 1,1 '-(1E,1 ' E)-(propane-1,2-diylbis(azan-1-yl-1-ylidene))bis (methan-1-yl-1-ylidene)dinaphthalen-2-ol, as electrocatalyst for hydrogen evolution reaction using acetic acid as the substrate. Both of the complexes have been synthesized under mild conditions and characterized by several methods. Single crystal X-ray structure of Complex 1 shows square planar geometry around nickel center. These complexes have effectively been used to reduce proton to generate hydrogen. Different control experiments have been carried out to understand the role of these catalysts and find their relevance in this regard. Turnover fre-quency (TOF) values for 1 and 2 have been determined as 653.1 and 777.5 s- 1, respectively. Hydrogen is evolved via reduction of metal center followed by formation of metal hydride species.

The synergistic effect of Pt–ZnO–Bi2O3 ternary heterojunction is observed and mechanistic paths are proposed for the photo-electrooxidation of methanol in alkali under visible light irradiation.

This paper proposes value addition to the classical Influence Maximization problem by introducing a quality measure to the participating nodes. The quality measure signifies the ‘ propensity to buy ’ of a customer (node) in a promotional marketing campaign context. Two metrics, Individual Net Worth (INW) and Neighborhood Net Worth (NNW) are proposed to measure the potential of a customer(s) in buying a given product. The proposed solution, through a heuristic approach, is capable of spreading the influence to the customers with a higher propensity to buy the product. The solution is scalable and adaptable to address user requirements. All these claims are substantiated through experimental results on public datasets. We performed a comparative study with notable algorithms in this domain. The result shows that the proposed approach selects seeds of higher quality as well as maximizes the overall quality (worth) of the influenced nodes in comparison to the notable algorithms, without any adverse impact on time complexity.

A simple single-step electrodeposition technique was followed for the three-dimensional (3D)-interconnected binary metallic manganese-cobalt sulfide nanosheets on nickel foam (MnCoS@NF). The architecture and chemical composition of the as-synthesized binder-free electrodes were analyzed by field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The MnCoS@NF achieves exceptionally high specific capacitance (1952.8 F g(-1) at 2 A g(-1)) along with high cycle stability in a three-electrode cell measurement. Furthermore, an aqueous asymmetric supercapacitor (AAS) device was designed using electrodeposited MnCoS@NF in combination with reduced graphene oxide-coated NF (rGO@NF) as a positrode and negatrode, respectively. This device was able to provide very high specific energy (105.1 W h kg(-1)) at a specific power (7.25 kW kg(-1)) along with high cyclic stability (93.9% of specific capacitance retained after 3000 consecutive GCD cycles), which demonstrates its excellent candidature in supercapacitor applications.

Scheduling of tasks with resource sharing and hard deadline in Real-Time Software Systems (RTSS) has been an important area of research. The Stack-Based Dynamic Resource access control Protocol (SDRP) is a new protocol that reduces the time complexity of the existing Stack-Based Resource Sharing Protocol (SRP) as well as prevents missing of deadline of a higher priority task having no resource requirement. The SDRP is simple, arguably much easier to understand and more efficient to implement compared to the SRP. A simulator is developed to validate the proposed protocol.

Three mononuclear Schiff-base–Ni(ii) complexes act as electrocatalyst for hydrogen evolution reaction using acetic acid and trifluoroacetic acid as the substrates. With the increase in chain length of ligand, efficiency of the catalyst decreases.

Studies of methanol electrooxidation reactions have achieved considerable advancements in the recent years for their encouraging contributions in the exciting fields of energy conversion and storage, organic syntheses, wastewater treatment, sensing, medicinal and environmental analyses, and many others thriving fields of modern technology. Accordingly, the fabrication of less expensive, efficient and decent quality electrocatalysts with high material stability, faster electro-oxidation kinetics, as well as less carbonation and decent corrosion inhibition activities are highly urged. Consequently, scientists around the globe are in continuous search for alternative economical smart anode-nanocatalysts for methanol oxidations with superior electrochemical performances. In the recent years, various inexpensive and readily-available nanocatalysts of non-noble metals like Ni, Co, Cu, etc., in reference to electrooxidation of organic molecules have been reported. The present work highlights the recent progress accomplished by rapidly flourishing nickel-based electrocatalysts for electrooxidation of methanol. The discussion comprehensively includes the basic mechanistic understandings and fundamentals for achieving high efficacy of methanol electrooxidation with nickel-based electrocatalysts. Also, the current challenges faced in this emerging area have been outlined to achieve superior, productive, and commercially viable catalysts for methanol electrooxidation in the near future.

Palladium–bismuth oxoiodide nanocomposites of various molar ratios of Pd and BiOI have been synthesized by the facile solvothermal method following the chemical reduction technique. The as-synthesized particles have been characterized by X-ray diffraction, spectrophotometric and microscopic studies. All the electrodes made of different Pd–BiOI nanocomposites show improved catalytic performance with synergistic effects for the oxidation of methanol in comparison with the pure components, Pd and BiOI. The modified graphite electrode containing a thin layer of Pd–BiOI composite having 10 mol% of Pd, designated as PB10, has shown the best electrocatalytic performance in comparison with other electrodes for methanol oxidation. The current density using PB10 is increased by 5.4 times with respect to Pd which is further improved by 6.4 times in the presence of visible light for methanol oxidation reaction. The retention of peak current at the 200th cycle of voltammetric operation is found to be 99.5% indicating significant stability of the electrodes. The study essentially suggests PB10 can be used as an efficient anode catalyst for oxidation of methanol in alkali.

Anatase, rutile and mixed anatase-rutile TiO2 are synthesized using a single pot sol-gel technique followed by variation of calcination temperature. The Pt decorated synthesized catalysts have been characterized by diffraction, spectroscopic and microscopic analyses. The cyclic voltammetry (CV) study reveals the increase of forward peak current density of methanol oxidation in alkali on Pt-anchored mixed-phase TiO2 (Pt/ARTiO2) (324.8 A g-1) by 4 and 2.5 times than that on Pt-containing rutile and anatase phases. The charge transfer conductance of the former electrode (1/184 omega- 1) is 5.7 and 8.7 times greater compare to that of the laters. The phase-dependent electrocatalytic activity of the electrodes and large retention (95%) of maximum peak current density at 500th CV cycle for the best electrode, are analyzed by different product selectivity of the electrodes. Pt/ARTiO2 is found to be the best current provider and reliable as it accelerates the formation of formate instead of carbonate.

The major findings in this report are (i) development of nanocomposite photocatalyst working through Z-scheme charge transfer pathway across the heterojunction, (ii) utilization of direct sunlight as the photo-source, and (iii) prospect of ligand-hole in photocatalysis through enhanced sub-band gap absorption. The photocatalysts, namely LaNiO3, g-C3N4 and LaNiO3/g-C3N4 nanocomposites were synthesized via facile route and were characterized for their structure, morphology, microstructure, texture, elemental mapping and surface oxidation states by using several physicochemical techniques. The photocatalytic performance of the nanocomposite was tested through the degradation of hazardous azo dye pollutants, namely reactive black 5 and methylene blue as well as the colorless antibiotic-pollutant tetracycline hydrochloride in aqueous solution in presence of natural sunlight with excellent recycling activity. The 10%LaNiO3/g-C3N4 nanocomposite sample shows the best catalytic activity, degrading respectively 94%, 98.6% and 88.1% of reactive black 5, methylene blue and tetracycline hydrochloride in 60,180 and 120 min. The photocatalytic activity of the nanocomposite phase is several times superior to that of the pure phases. The improvements of photocatalytic activity of g-C3N4 in the nanocomposite have been rationalized through the construction of direct Z-scheme heterojunction and suppression of electron-hole pair recombination efficiency. The enhanced photo-absorption of the nanocomposite can possibly be related to sub-bandgap absorption, which is associated to the midgap state originating from ligand-hole formation or defects in the structure. The photodegradation process is mediated through the formation of super oxide radical (_O2) and hole (h thorn ) as the main responsible species. (c) 2021 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.