Nickel-doped lanthanum cerate nanomaterials as highly active electrocatalysts.

The efficient oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalyst materials are crucial in the energy research domain due to their tunability. Structural modification in perovskites such as lanthanum cerates (LaCeO3) upon doping at A or B sites significantly affects the surface activity and enhances the catalysis efficacy. Herein, B-site nickel-doped lanthanum cerate (LaCe1-xNixO3±Î´) nanopowders were applied as ORR indicators in high-temperature electrochemical impedance spectroscopy for solid-oxide fuel cell (SOFC) tests and in cyclic voltammetric OER investigations in alkaline medium. The integration into SOFC applications, via solid-state EIS in a co-pressed three-layered cell with LCNiO as cathode, is investigated in an oxygen-methane environment and reveals augmented conductivity with temperatures of 700-850°C. The higher electrokinetic parameters-including diffusion coefficients, Do heterogeneous rate constant, ko, and peak current density for OER in KOH-methanol at a LCNiO-9-modified glassy carbon electrode-serve as robust gauges of catalytic performance. CV indicators and EIS conductivities of LaCe1-xNixO3±Î´ nanomaterials indicate promising potencies for electrocatalytic energy applications.

Sol-Gel Synthesized High Entropy Metal Oxides as High-Performance Catalysts for Electrochemical Water Oxidation.

Hexanary high-entropy oxides (HEOs) were synthesized through the mechanochemical sol-gel method for electrocatalytic water oxidation reaction (WOR). As-synthesized catalysts were subjected to characterization, including X-ray diffraction (XRD), Fourier transforms infrared (FTIR) analysis, and scanning electron microscopy (SEM). All the oxide systems exhibited sharp diffraction peaks in XRD patterns indicating the defined crystal structure. Strong absorption between 400-700 cm-1 in FTIR indicated the formation of metal-oxide bonds in all HEO systems. WOR was investigated via cyclic voltammetry using HEOs as electrode platforms, 1M KOH as the basic medium, and 1M methanol (CH3OH) as the facilitator. Voltammetric profiles for both equiatomic (EHEOs) and non-equiatomic (NEHEOs) were investigated, and NEHEOs exhibited the maximum current output for WOR. Moreover, methanol addition improved the current profiles, thus leading to the electrode utility in direct methanol fuel cells as a sequential increase in methanol concentration from 1M to 2M enhanced the OER current density from 61.4 to 94.3 mA cm-2 using NEHEO. The NEHEOs comprising a greater percentage of Al, ([Al0.35(Mg, Fe, Cu, Ni, Co)0.65]3O4) displayed high WOR catalytic performance with the maximum diffusion coefficient, D° (10.90 cm2 s-1) and heterogeneous rate constant, k° (7.98 cm s-1) values. These primary findings from the EC processes for WOR provide the foundation for their applications in high-energy devices. Conclusively, HEOs are proven as novel and efficient catalytic platforms for electrochemical water oxidation.

Electrochemical investigations of DNA-Intercalation potency of bisnitrophenoxy compounds with different alkyl chain lengths.

In this study, the binding tendency of bisnitrophenoxy compounds (BN) having different methylene (-CH2-)n spacer groups (n = 8-11) with fish sperm double stranded deoxyribonucleic acid (dsDNA) was explored. Cyclic voltammetry (CV) was used to evaluate various kinetic and binding parameters (Ks,h, Do, K b and binding site sizes). Performed electrochemical studies designated strong contact of these symmetric molecules with dsDNA in threading intercalation mode of binding. The number (n) of methylene spacer group in the molecular structure of bisnitrophenoxy compounds, e.g., BN-8 (1-nitro-4-(8-(4-nitrophenoxy)octyloxy)benzene, was observed to have a strong influence on their binding affinity. Decreased peak current values and positively shifted peak potentials recorded via cyclic voltammetry clearly depicted that bisnitrophenoxy compounds can intercalate with dsDNA. Results demonstrated the following order of binding constants; K b (M-1): BN-8 (2.32 × 104) < BN-9 (5.73 × 104) < BN-10 (8.97 × 104) < BN-11 (17.34 × 104). The order of increasing binding sites from BN-8 (0.13) to BN-11 (1.38), revealed the maximum threading intercalation strength by bisnitrophenoxy compound having the longest methylene spacer (n = 11). Thermodynamic studies augmented the strong binding of BN-11 with dsDNA as compared to BN-8 because of the long-chain, -CH2- spacer in its structure. The spontaneity of dsDNA-binding was revealed by the negative ΔG values for interaction of all the compounds. Moreover, binding parameters from thermodynamic and kinetic studies also corresponded to the threading intercalation mode of interaction, which itself points to the potency of the envisioned drug-like molecules.

Engineering electroactive and biocompatible tetra(aniline)-based terpolymers with tunable intrinsic antioxidant properties in vivo.

Under different pathological conditions, high levels of reactive oxygen species (ROS) cause substantial damage to multiple organs. To counter these ROS levels in multiple organs, we have engineered highly potent novel terpolymers. We found that combination of FDA-approved polyethylene glycol, fumaric acid moieties and electroactive tetra(aniline) by varying the content of tetra(aniline) results into a novel drug composition with biologically active and tunable intrinsic antioxidant properties. To test the intrinsic antioxidative properties of these novel terpolymers, we used alloxan to induce diabetes in rats where ROS generation is known to be higher. The systemic administration of terpolymers to the diabetic rats showed strong electroactive antioxidant behavior which not only normalized ROS levels, but also improved the levels of enzymatic antioxidants including superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH). As a proof-of-principle, we here show TANI based novel drug composition of terpolymers with tunable intrinsic antioxidant properties in multiple organs.

Biferrocenyl Schiff bases as efficient corrosion inhibitors for an aluminium alloy in HCl solution: a combined experimental and theoretical study.

The corrosion inhibitive capabilities of some ferrocene-based Schiff bases on aluminium alloy AA2219-T6 in acidic medium were investigated using Tafel polarization, electrochemical impedance spectroscopy (EIS), weight loss measurement, FT-IR spectroscopy and scanning electron microscopic (SEM) techniques. The influence of molecular configuration on the corrosion inhibition behavior has been explored by quantum chemical calculation. Ferrocenyl Schiff bases 4,4'-((((ethane-1,2-diylbis(oxy))bis(4,1-phenylene))bis(methaneylylidene))bis(azaneylylidene))bisferrocene (Fcua), 4,4'-((((ethane-1,2-diylbis(oxy))bis(2-methoxy-1,4-phenylene))bis(methaneylylidene))bis(azaneylylidene))bisferrocene (Fcub) and 4,4'-((((ethane-1,2-diylbis(oxy))bis(2-ethoxy-1,4-phenylene))bis(methaneylylidene))bis(azaneylylidene))bisferrocene (Fcuc) have been synthesized and characterized by FT-IR, 1H and 13C NMR spectroscopic studies. These compounds showed a substantial corrosion inhibition against aluminium alloy in 0.1 M of HCl at 298 K. Fcub and Fcuc showed better anticorrosion efficiency as compared with Fcua due to the electron donating methoxy and ethoxy group substitutions, respectively. Polarization curves also indicated that the studied biferrocenyl Schiff bases were mixed type anticorrosive materials. The inhibition of the aluminium alloy surface by biferrocenyl Schiff bases was evidenced through scanning electron microscopy (SEM) studies. Semi-empirical quantum mechanical studies revealed a correlation between corrosion inhibition efficiency and structural functionalities.