P-block tin single atom catalyst for improved electrochemistry in lithium-sulfur battery: a theoretical and experimental study

Main group metals are routinely considered as catalytically inactive hence never employed for optimizing the lithium-sulfur electrochemistry. Herein, density function theory calculations reveal that atomically dispersed tin on nitrogen doped...

Communication—Fe-MOF Exhibits Higher Oxygen Evolution Ability by Electronic Modulation of Sodium Hypochlorite

Development of robust alkaline oxygen evolution reaction electrocatalysts is crucial for the efficiency of water splitting. Herein, Fe-MOF nanocones array on nickel foam are synthesized by introducing sodium hypochlorite, leading to Cl substitution of terephthalic acid in Fe-MOFs (Fe-MOF-Cl/NF). Experimental results show that Fe-MOF-Cl/NF exhibits enhanced OER activity over Fe-MOF/NF, lowering η50 from 292.4 to 222.7 mV. In combination with density function theory calculations, the improved OER performance is attributed to engineering electronic structure of Fe sites which accelerate the third step from *O to *OOH, and promote OER kinetics. Additionally, Fe-MOF-Cl/NF can retain catalytic activity for 100 h.

Metal incorporated aminothiazole-derived compounds: synthesis, density function theory analysis, in vitro antibacterial and antioxidant evaluation

The present study advocates the combined experimental and computational study of metal-based aminothiazole-derived Schiff base ligands. The structure and electronic properties of ligands have been experimentally studied by spectroscopic methods (UV-Vis, FT-IR, 1 H-NMR and 13 C-NMR), mass spectrometry, elemental analysis and theoretically by density function theory (DFT). Computational calculations employing the B3LYP/6-31 + G(d,p) functional of DFT were executed to explore the optimized geometrical structures of ligands along with geometric parameters, molecular electrostatic potential (MEP) surfaces and frontier molecular orbital (FMO) energies. Global reactivity parameters estimated from FMO energy gaps signified the bioactive nature of ligands. The synthesized ligands were used for chelation with 3 d -transition metals [VO(IV), Cr(III), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] in 1 : 2 (metal : ligand) molar ratio. The spectral and magnetic results confirmed the formation of octahedral geometry around all the divalent and trivalent metal centres, whereas the tetravalent vanadyl centres were confirmed to have square-pyramidal geometry. All the as-synthesized compounds were investigated for in vitro antibacterial potential against two Gram-negative ( Salmonella typhimurium and Escherichia coli ) and two Gram-positive ( Bacillus subtilis and Staphylococcus aureus ) bacteria. Antibacterial assay results displayed pronounced activity, and their activity is comparable to that of a standard drug (streptomycin). The antioxidant potential of these compounds was assessed by employing diphenyl picryl hydrazide radical scavenging activity. The results displayed that all the metal chelates have exhibited more bioactivity in contrast with free ligands. The chelation was the main reason for their enhanced bioactivity. These results indicated that the thiazole metal-based compounds could be exploited as antioxidant and antimicrobial candidates.

Design Pollution Gas Sensor Using Graphene Ribbon: Density Function Theory (DFT)

Density Function theory (DFT) calculation used to employed ground and excitation states for graphene ribbons, types of adsorption, energy gap, maximum wave length and optical band gap. Adsorption energy showed that CO2 gas molecule have chemical adsorption in distance 1 and 1.5 Angstrom, distance 2 and 2.5 Angstrom appear physical adsorption, adsorption energy decreased when distance between surface and gas molecule increasing. Resulting from chemical adsorption energy gap change with distance 1 and 1.5 Angstrom because attract gas molecule with surface. Excitation energy for nano system in sample 1 and 4 shifted to low wavelength (blue shift) change from 1018 nm to 993 nm and 718 nm on series. Other sample have red shift and energy gap becoming open. Result showed that graphene ribbon sense carbon dioxide gas (CO2).

Conceptualized Simulation for Templating Carbon Based Nano Structures for Li-ion Batteries: A DFT Investigation

CNT (10, 0) is carbon nanotube; Graphene is a 2-dimensional carbon allotrope being light weight and Chitosan is a linear polysaccharide. In this work, detailed analysis of the above three stated compounds as anode for lithium-ion batteries is stated. The density function theory (DFT) computations were used to carry out the investigation of the above stated compound as anode materials for the lithium-ion batteries. The analysis shows that Graphene and Chitosan are highly favorable to be used as anodes materials for the lithium-ion batteries. The results show that the Vcell of Graphene and Chitosan when they are used as an anode for lithium-ion batteries are extremely higher as compared to CNT (10, 0) at 5.632 Volts, 4.719 Volts and 1.22 Volts, respectively.