Syed Shoaib Ahmad Shah

In this paper, the facile synthesis of graphene oxide and MOF based composite material for the demanded adsorption of leading antibiotic is reported. The adsorbent showed good results for removal of norfloxacin with high adsorption capacity (1114.82 mg/g) and removal efficiency (93.61 %). In addition, Langmuir model proved most suitable with highest value of R 2 ¼ 0.99929 among three applied isothermal models. The thermodynamic study showed spontaneous and exothermic (DH ¼ À1.1Â10 À5 Kj/ mol, DG ¼ À13324.33 Kj/ mol) nature of adsorption process with reusability of 88.4 % after several cycles. Moreover, statistical analysis and mechanistic study were also performed. HIGHLIGHTS Synthesis of graphene oxide and MOF based composite material High surface area, void spaces, open metal sites, and tunable morphology. Adsorption of leading antibiotic (norfloxacin). MOF/GO composite with high water stability and reuseability. Isothermal, kinetic, statistical and mechanistic study. ARTICLE HISTORY

Two-dimensional graphene-based materials are of great interest in electrochemical energy storage devices owing to their high theoretical specific capacitance; however, it is a big challenge to approach the theoretical limit. Here, we report a facile strategy for the selective production of N-doped graphene nanosheets (NGNS) in quasi-closed montmorillonite (MMT), which act as a nanoreactor and open only along the perimeter to enable the entrance of aniline (AN) monomer. As a proof of concept applications, as-synthesized NGNS are used as the electrode material for a symmetric supercapacitor (SSC). The NGNS supported on carbon paper (NGNS@CP) exhibits excellent capacitive performance in an aqueous neutral electrolyte (LiCl) by achieving a high capacitance of 480 and 472 F g À1 at 1 A g À1 for negative and positive electrodes, respectively. The NGNS@CP electrode also shown outstanding rate capabilities and cycling stabilities in positive and negative voltage windows by retaining the 98.07, and 99.44 % of the original value, respectively. Moreover, the assembled flexible symmetric supercapacitor (NGNS@CP//NGNS@CP) using LiCl/PVA hydro-gel electrolyte can operate at high voltage window of 0.0e2.0 V and achieved an ultra-high energy density of 82.72 Wh kg À1 at a moderate power density of 425.68 W kg À1 with remarkable cycling stability of 96.91 % over 10000 charge/discharge cycles. Furthermore, the NGNS@CP// NGNS@CP demonstrates excellent flexibility and one device can power the two light-emitting diodes brightly. The achieved energy density of the NGNS@CP//NGNS@CP is much superior to the previous graphene-based SSCs and suggests a new generation of ultra-fast symmetric supercapacitor as novel high-performance energy storage devices.

Here, we develop inert V 2 O 3 oxide to enhance the HER activity of industrial Ni catalysts with the assistance of abundant metal/oxide interfaces. The as-synthesized Ni/V 2 O 3 catalyst exhibits over 5 times the activity of a pure Ni sample due to the particle size control and metal/oxide interaction, and excellent durability as a result of oxide anchoring. Hydrogen production via water electrolysis is an effective method to store the intermittent electric power generated from large-scale renewable energy. 1-4 Developing stable and active hydrogen evolution reaction (HER) catalysts based on cheap transition metals is extremely desirable for water electrolysis in industrial-scale applications. 5-9 Nickel (Ni) is the most common HER catalyst used for industrial water electrolysis in basic solutions, 10-12 owing to its chemical stability, earth abundance, excellent conductivity, etc. However, the Ni metal is still not as competent as an ideal water reduction catalyst due to its high overpotential and large Tafel slope. 6 Besides, Ni undergoes serious deactivation as a cathode during water electrolysis in an alkaline solution. 13 Hence, maximizing the potential of Ni to its ultimate limit via facile routes is a great challenge and a trending issue today. A rational design and fabrication of sufficient active interfaces between metal and oxide seems to be an effective strategy to facilitate the catalytic performances of metal-based catalysts. Recently, various metals such as Pt, Pd, Au, Cu, and Ni supported on reducible metal oxides (e.g., TiO x , CeO x , and FeO x) have been reported to exhibit improved catalytic properties for a number of important reactions, including CO oxidation , CO 2 hydrogenation, and water-gas shift reactions. 14-24 In our pervious work, the nature of the interface-induced synergistic effect of metal/metal oxide composite catalysts for alkaline HER has been deeply studied and a ''chimney effect'' of metal/metal oxide for the improved HER activity has been identified. 25 By means of DFT calculation, the neighbouring sites of the interface are immune to the H 2 O* and OH* adsorption, but beneficial for the smooth adsorption/ desorption of the reactant (H*) to form product H 2. The special adsorption/desorption behaviour of the reactant species greatly accelerated the HER process and the hydrogen product could be manufactured continuously through the metal/oxide interface like a ''chimney''. However, all those reported metal/oxide catalysts involve reducible metal cations in oxides, and promotional effects of non-reducible metal oxides (also known as inert oxides) are rarely reported. Herein, we demonstrate that inert V 2 O 3 greatly promotes the HER activity of Ni by creating highly active metal/oxide interfaces. In this work, highly dispersed ultrafine metallic Ni nanoparticles on V 2 O 3 oxide (Ni/V 2 O 3) were designed and fabricated by selectively segregating the Ni element in the original mixed metal oxide to the surface of the inert metal oxide. The inert V 2 O 3 not only provides anchoring sites for size control and uniform dispersion of the Ni nanoparticles but also serves as electron conduction pathways during electrocatalytic processes. Besides, the metallic Ni migrated towards the surface of V 2 O 3 in situ generate the desired Ni/V 2 O 3 interfaces, which greatly promote the dissociation of water molecules and lower the hydrogen binding energy. Benefitting from the combined effects of particle size control, oxide anchoring, and metal/oxide interaction, the elaborately designed Ni/V 2 O 3 exhibits a higher activity for HER with a low overpotential of À140 mV at À10 mA cm À2 , a small Tafel slope (À112 mV dec À1), and improved stability for over 18 h during operation in a basic solution. The inert V 2 O 3 supported ultrafine Ni nanoparticles was synthesized through hydrogen reduction from the Ni x V 1Àx O 2 precursor with a uniform Ni incorporation. During the hydrogen treatment, the Ni element grew out of the original precursors as the Ni ions migrated towards the surface and were reduced by H 2. The morphologies of the Ni x V 1Àx O 2 precursors

Cobalt/iron oxide nanoparticles (CFO/NPs) were fabricated with a facile solid combustion method and decorated on poly-aniline-derived porous N-doped carbon nanosheets. The N-doped carbon nanosheets provide a pathway for charge transfer and act as defensive layers to avoid the agglomeration of nanoparticles. The decoration of CFO nanoparticles on porous N-doped carbon nanosheets (CFO/NC) typically leads to hybrid material that displays an exceptionally high electrochemical performance for Li-ion batteries (LIBs) with excellent diffusion of electrolyte ions and ensures fast Li + /e − transport. The initial discharge capacity reaches up to 1270 mAh g −1 (1.65 mAh cm −2) at a current density of 500 mA g −1 (0.65 mA cm − 2). Furthermore, it also exhibits an exceptionally high specific capacity of 635 mAh g −1 at a high current density of 500 mA g −1 (500 mA g −1) after long cycling (250 cycles) and a remarkable rate capability with 93% capacity retention. These excellent electrochemical characteristics demonstrate that CFO/NC is a promising anode material for LIBs. Graphical abstract Keywords Binary oxide · N-doped carbon nanosheet · Anode material · Lithium-ion battery

Low-cost and efficient electrocatalysts for water splitting hold a significant position in future renewable energy system. Herein, we first fabricated a self-standing bimetallic FeCo Prussian blue analogue nanosheet array (FeCo PBA) on Ni foam through ion exchange between K 3 [Fe(CN) 6 ] and hydrothermal synthesized Co 3 (PO 4) 2 $8H 2 O nanosheet arrays. Then the obtained FeCo PBA were facilely transformed into FeCo/C and FeCoP/C nanosheet arrays through hydrogenation and phosphidation, respectively. Benefiting from the enhanced mass transfer in porous structure, the intimate contact with Ni framework and the synergistic effect of bimetal sites, the resultant FeCo/C NS and FeCoP/C NS demonstrate superior oxygen and hydrogen evolution activity in alkaline media, respectively. Impressively, a low cell voltage of 1.55 V is sufficient to afford a current density of 10 mA cm À2 by coupling FeCo/C NS and FeCoP/C NS in a two-electrode water splitting electrolyzer, surpassing the performance of PtC based couple (V cell,10 ¼ 1.60 V). This work provides a new approach to construct highly efficient and cost-effective water splitting electrodes.

Electrocatalysts are readily poisoned during the catalysis of the oxygen reduction reaction (ORR);e ven air containing traces of SO x and/or NO x significantly decrease the activity and the durability of H 2-O 2 fuel cells.N ow,ametal-free strategy is reported to develop an efficient anti-poisoning ORR catalyst, which involves the pyrolysis of PDAP-phytic acid super-molecular aggregate (PPSA). The pyrolyzed co-doped carbon acting as am etal-free electrocatalyst shows an enhanced activity for ORR in acidic medium, even under poisoning conditions (SO x ,N O x ,a nd PO x). Moreover,P-doping also changes the ORR pathwayb yy ielding less than 4% of H 2 O 2 ,indicating afour-electron pathway whereas more than > 20 %o fH 2 O 2 was recorded for N-doped carbon synthesized from PDAP.

With the growing energy demand for a low carbon economy, it is important to develop new materials that can enhance the effectiveness of energy storage and energy conversion systems. We report a kinetics-controlled reaction for the synthesis of bimetallic organic frameworks. Furthermore, uniform ZnCoS@CoS yolk-shell structures were fabricated via sulfidation and then converted to ZnCoS@Co 9 S 8 / N-doped carbon single-holed hollow core-shell structures by calci-nation under nitrogen. Such a core-shell structure effectively withstands the dramatic volume change and inhibits the aggregation of metal nanoparticles. Meanwhile, the N-doped porous carbon offers fast electron transport to achieve exceptionally high rate capability. As a result, single-holed hollow core-shell ZnCoS@Co 9 S 8 /N-doped carbon shows admirable electrochemical activity as an anode material in lithium ion batteries. Furthermore, this paper also discloses the synergistic effect of the chalcogenide phase and metal on the Li storage capability.

Oxygen evolution reaction (OER), as an important half-reaction involved in water splitting, has been intensely studied since the last century. Transition metal phosphide and sulfide-based compounds have attracted increasing attention as active OER catalysts due to their excellent physical and chemical characters, and massive efforts have been devoted to improving the phosphide and sul-fide-based materials with better activity and stability in recent years. In this review, the recent progress on phosphide and sulfide-based OER electrocatalysts in terms of chemical properties, synthetic methodologies, catalytic performances evaluation and improvement strategy is reviewed. The most accepted reaction pathways as well as the thermodynamics and electrochemistry of the OER are firstly introduced in brief, followed by a summary of the recent research and optimization strategy of phosphide and sulfide-based OER electrocatalysts. Finally, some mechanistic studies of the active phase of phosphide and sulfide-based compounds are discussed to give insight into the nature of active catalytic sites. It is expected to indicate guidance for further improving the performances of phosphide and sulfide-based OER electrocatalysts.

In this paper NiP , RuO 2 and RuO 2 /Ni-P composites were deposited on Ni plates through pulsed elec-trodeposition method, and their activities for HER in alkaline solution were studied comparatively. Scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelec-tron spectroscopy (XPS) analysis confirmed the formation of every composite. The electrochemical impedance spectroscopy (EIS) showed that Ni-P/Ni had lower charge transfer resistance at high over-potential and higher charge transfer resistance at low overpotential than RuO 2 /Ni. While Ni-P/Ni exhibited lower catalytic activity for HER at low overpotential and higher catalytic activity at high overpotential than RuO 2 /Ni. Meanwhile, RuO 2 /Ni-P/Ni had the lowest charge transfer resistance and highest catalytic activity among the three electrodes at both low and high overpotentials. It indicated that RuO 2 /Ni-P/Ni with less NiP and RuO 2 exhibited enhanced catalytic activity for HER than both RuO 2 / Ni and Ni-P/Ni, due to an electron charge transfer synergistic effect of RuO 2 and NiP .

Background: Nano-Metal-organic frameworks (NMOFs) have stable pores in their assembly. In the recent era, these have been used in biomedicine, magnetic and electronic devices and sensors. MOFs also have a potential concern in biomedical applications, a new substitute of therapeutic and/or diagnostic materials, among others. Initially, NMOFs have been used as delivery vehicles for imaging contrast agents and molecular therapeutics. Discussion: Subsequently, several paramagnetic metal ions carrying capacity of NMOFs has been extensive explored as magnetic resonance imaging (MRI) contrast agents. Gd 3+ and Mn 2+ , both in NMOFs have shown brilliant efficiency as T1-weighted contrast agents with large per metal-and per particle-based MR relaxivities. In this review, the focus is mostly over the uses of NMOFs in imaging techniques, also discussing some significant models of micrometric MOFs that have been discovered to date in the biomedical arena. Conclusion: The ready internalization of NMOFs by cells rendered their applications in sensing biologically relevant molecules such as Ca 2+ and NO responsible for signal transduction, Na + / K + responsible for ion channels and proton pumps, Cl-responsible for osmotic pressure, and other processes in live cells.

This review is based on the analysis of recent developments on cyanation reactions for the synthesis of nitriles (RCN) through transition metal mediated cyanation reaction as well as by using non-metal like iodine (transition metal free system). In this regard, various catalyzed systems were reviewed to find the most efficient method having acceptable reaction system with surely less cost, mild conditions with easy handling. For the synthesis of nitriles; Copper, Palladium, Rhodium, and Iodine-based catalyzed systems have been explored for various aryl halides, arenes, pyridine, quinolone, imidazole, thiophenol, b-keto esters/amides, 2-arylbenzothiazoles etc. These reactions underwent with different time rates having the corresponding nitriles leading to natural products derivative in moderate to good yields.

Metal organic frameworks (MOFs) have been considered as promising candidates for excellent electrocatalysts. Herein, we report a controllable synthesis of CoN -C electrocatalysts derived from Zn/Co bimetallic organic frameworks (Zn/Co-MOFs). The elimination of Zn is simultaneously taken place during the pyrolysis due to its low boiling point, resulting in a very mesoporous assembly with homogeneous Co distribution in N-C framework. Zn also facilitates the dispersion of Co in the Zn/Co-MOF, which efficiently hinders the agglomeration of Co during carbonization. The results show that CoN -C catalysts synthesized from 22.5% Co containing in the Zn/Co-MOF precursor gives the best ORR activity in alkaline solution with its half wave potential of 0.91 V vs. RHE and current density of 3.0 mA/cm 2 , which is even better than those of commercial Pt/C catalysts. The high activity and current density are mainly attributed to the extremely well dispersed Co nanoparticles and the mesoporous nature.

Quinoxalines display diverse and interesting pharmacological activities as antibacterial, antiviral, antiparasitic and anticancer agents. Particularly, their 1ˏ4-diN oxide derivatives have proved to be cytotoxic agents that are active under hypoxic conditions as that of solid tumours. A new series of quinoxaline 1ˏ4-diN oxide substitutes at 7-position with esters group were synthetized and characterized by infrared (IR), proton nuclear magnetic resonance (1 H-NMR), spectroscopy, and elemental analysis. Seventeen derivatives (M1-M3, E1-E8, P1-P3 and DR1-DR3) were selected and evaluated for antitumor activities using the NCI-60 human tumor cell lines screen. Results showed that E7, P3 and E6 were the most active compounds against the cell lines tested. Substitutions at 7-position with esters group not necessarily affect the biological activity, but the nature of the esters group could exert an influence on the selectivity. Additionally, substitutions at 2-position influenced the cytotoxic activity of the compounds.

Different weights of amorphous NiP alloy with same P contents were electrodeposited on nickel plate with same area used as cathode for hydrogen evolution reaction (HER). The amorphous NiP alloy coatings were characterized for their surface morphology and composition through Scanning electron mi-croscopy (SEM) and Energy dispersive X-ray spectroscopy (EDS) techniques, X-ray photoelectron spec-troscopy (XPS) and X-ray diffraction (XRD) analysis. The electrocatalytic activity for HER in alkaline medium is determined by linear scan voltammetry (LSV) and a relationship between HER activity and capacitance is established. The capacitance varies with the loading of the NiP on Ni plate but the activity for HER is directly proportional to the capacitance in alkaline and vice versa. 3#Ni-P/Ni containing 3.85 mg NiP alloy with highest capacitance performs the best catalytic activity. This work provides direct evidence to explore the capacitance influence on the electrocatalystic activity for the HER.

Flexible supercapacitors (SCs) are an emergent and promising technology for next-generation energy storage devices. However, low energy densities hindered their practical applications. Two-dimensional (2D) nanosheets can exhibit excellent electrochemical charge storage properties due to their short ion-diffusion distance and rich electroactive sites with multiple valence states. Herein, we report the direct growth of mesoporous 2D zinc cobaltite nanosheets on a flexible carbon cloth substrate (Zn-Co-O@CC) with an average thickness of $45 nm by a facile hydrothermal method at low temperature. The Zn-Co-O@CC electrode displays a high capaci-tance of 1750, 1573.65 and 1434.37 F g À1 at a current density of 1.5 A g À1 in LiCl, NaCl and KCl neutral aqueous electrolytes, respectively , with excellent rate capabilities at high current densities and demonstrates good cycling stability (>94%) for up to 5000 cycles. Moreover, highly flexible asymmetric supercapacitor (ASC) devices have been fabricated using Zn-Co-O@CC as a positive electrode and bimetallic organic framework (MOF)-derived nanoporous carbon polyhedra (NPC@CC) as a negative electrode (Zn-Co-O@CC// NPC@CC). The as-fabricated ASC can operate at a large potential window of 0.0-2.0 V and shows outstanding energy storage performance by delivering an ultra-high energy density of 117.92 W h kg À1 at a power density of 1490.4 W kg À1 with a cycling stability of 94% after 5000 charge/discharge cycles. To the best of our knowledge, the achieved energy storage performance of the ASC device is very competitive and the highest among all binary metal oxides, carbona-ceous materials, and MXene-based SCs and ASCs to date. The applied strategy to fabricate SCs is capable of enhancing both electrochemical activity and cycling stability, and can be readily applied to other metal oxide-based SCs.

Advances in the use of organotin(IV) compounds have gained relevant interest in both the chemical and pharmaceutical industry. Tin(IV) form stable complexes with a unique structure and physicochemical properties that are used in organic synthesis as heat stabilizers and catalysts, in drug development as biologically active agents, and in other areas. This review focuses on recent progress in the classical and convenient synthesis procedure, on their mechanism of action, and biological activities as antitumoral and antimicrobial agents.

A modified method for the synthesis of a series of substituted benzenesulfonamides from benzenesulfonylchlo-
ride  and substituted  amines (1:1) in  aqueous media have been adopted at controlled pH (8-10). Transition metal com-
plexes of synthesized ligands were also prepared by refluxing ligands and metal salts (2:1) for one hour. The synthesized
compounds have been characterized by spectroscopic  techniques  (FTIR,
1
HNMR  and mass  spectrometry). Synthesized
compounds were analyzed for their activity toward acetyl cholinesterase (AChE) inhibition, butyrylcholinesterase (BChE)
inhibition, lipoxygenase (LOX) inhibition, antioxidant (DPPH) and antiurease. As regards biological activities of ligands,
only N-(2-nitrophenyl) benzenesulfonamide (3) showed appreciated value of IC 50 = 77.13± 00
mole against LOX while
all metal complexes showed low activities. Cu complex (C-4) showed moderate activity against LOX while all the other
metal complexes had no activity against any enzyme at all. Similarly Zn complexes (Z-2 to Z-6) showed little activity
against AChE but the ligands showed no significant activity against any other. Metal complexes showed high capacity
toward antiurease activity.

Summary: Mycotoxins are natural secondary metabolites produced by fungi on agricultural
commodities during growth in the field under a wide range of climatic conditions and can elicit
deleterious effects on other organisms. Furthermore, during storage, wide range of fungi under
favorable  conditions  can  cause  the  mycotoxins  contamination.  The  Food and Agriculture
Organization has estimated that the secondary metabolites produced by fungi affects approximately
quarter of the world’s food crops, including many basic foodstuffs and feeds for animal. Intake of
contaminated agricultural products or foods of animal origin i.e. milk or eggs are the major routes
of mycotoxin exposure to human beings. In addition to these sources, mycotoxin enters the body
through the dermal contact or inhalation from dust or molds. Mycotoxins contained in moldy foods,
or damp interiors, can cause diseases in humans and animals such as various types of cancer,
hepatic diseases, and immune and neurological disorders. Research and retrospective data of more
than 100 studies are summarized with more than 170 citations in the form of tables with respect to
country; type of mycotoxin metabolite, sample origin, exposure measurement technique and its
range human milk, blood, urine, and other human fluids/tissues from more than 35 countries is
presented in this review. The presented database would be valuable benchmark information for
development for the future research and for setting priorities in food handling and storage.

Transition metal-based compounds constitute a distinct class of chemotherapeutics
extensively used in the clinic as antitumor and antiviral agents. However, drug resistance
and side effects of established antitumor metallodrugs such as cisplatin [cis-
diamminedichloroplatinum (II)] and its analogues, carboplatin and oxaliplatin, have limited
their clinical utility. These limitations have prompted a search for more effective and less
toxic metal-based antitumor agents. The unique properties of metal ions, such as redox ...

Abstract: Compounds derived from nature have played a major role in drug discovery. They became the basis for the
development of new pharmaceuticals. In this scope, family Cucurbitaceae is a prominent source of secondary metabolites,
mainly triterpenoids. In this paper, we provide a brief review of cucurbitane metabolites that exhibit an extensive range of
biological actions specifically antidiabetic, anti-inflammatory, cytotoxic, hepatoprotective, and antiparasitic effects.