Hydrogen evolution reaction on Pt and Ru in alkali with volmer-step promotors and electronic structure modulators

Alkaline water electrolysis despite having a variety of choices for anodic oxygen evolution reaction (OER) catalysts out of non-precious metals suffers significantly due to the poor kinetics of cathodic hydrogen evolution reaction (HER) even with the state-of-the-art Pt and equally active Ru. The Volmer-step (water dissociation (WD) coupled proton adsorption) of alkaline HER is mostly the rate-determining step (RDS) and costs most of the work required. In this review, recent developments in improving the HER kinetics of Pt and Ru with Volmer-step promotors and electronic structure modulators have been comprehensively analyzed and critically presented with the challenges and prospects.     

Determining the feasibility of H2O2 production at a graphite cathode using bond dissociation energy: comparing simple and nitrogen doped cathodes

Research on Chemical Intermediates - Hydrogen peroxide (H2O2) is commercially produced by catalytic oxidation of anthrahydroquinone, which is energy-intensive. Electrochemical production of...     

Catalysts and temperature driven melt polycondensation reaction for helical poly(ester‐urethane)s based on natural L‐amino acids

Catalyst and temperature driven melt polycondensation reaction was developed for natural L‐amino acid monomers to produce new classes of poly(ester‐urethane)s. Wide ranges of catalysts from alkali, alkali earth metal, transition metal and lanthanides were developed for the condensation of amino acid monomers with diols to yield poly(ester‐urethane)s. A‐B Diblock and A‐B‐A triblock species were obtained by carefully choosing mono‐ or diols in model reactions. More than two dozens of transition metal and lanthanide catalysts were identified for the polycondensation to yield high molecular weight poly(ester‐urethane)s. Theoretical studies revealed that the carbonyl carbon in ester possessed low electron density compared to the carbonyl carbon in urethane which driven the thermo‐selective polymerization process. Optical purity of the L‐amino acid residues in the melt polycondensation process was investigated using D‐ and L‐isomers and the resultant products were analyzed by chiral‐HPLC and CD spectroscopy. CD analysis revealed that the amino acid based polymers were self‐assembled as β‐sheet and polyproline type II secondary structures. Electron and atomic force microscopic analysis confirmed the formation of helical nano‐fibrous morphology in poly(ester‐urethane)s. The newly developed melt polycondensation process is very efficient and optimized for wide range of catalysts to produce diverse polymer structures from natural L‐amino acids. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1065–1077     

Evaluation and comparison of global scalar properties for the simultaneous interaction of ionic liquids with thiophene and pyridine

Ab initio studies were carried out with mixtures containing ionic liquid with thiophene and pyridine for studying the simultaneous interaction. Global scalar properties such as HOMO/LUMO energies, HOMO–LUMO energy gap, chemical hardness, chemical potential, electronegativity, global hardness, global softness and electrophilicity index were determined for clusters containing ionic liquids with thiophene and pyridine. Ionic liquids containing: 1-butyl-3-methylpyrrolidinium [BUMPYR], 1-benzyl-3-methyimidazolioum [BeMIM] and 1-butyl-3-methylpyridinium [BUMPY] cations combined with inorganic anions containing fluorine ([BF₄] and [PF₆]) were studied in this work. [BeMIM][BF₄] (1-benzyl-3-methyimidazolioum tetrafluoroborate) with a HOMO–LUMO energy gap of 0.1882 Hartrees was found to be the most effective IL. Further a ranking based on all the mentioned scalar parameters also pointed out [BeMIM][BF₄] to be the most desirable IL. The overall ranking after taking into considerations all factors followed: [BeMIM][BF₄] > [BUMPYR][BF₄] > [BUMPY][PF₆] > [BUMPY][BF₄] > [BUMPYR][PF₆]. To validate the findings, infinite dilution activity coefficients were predicted using the quantum chemical based COSMO-RS methodology which gave the same trend as observed using scalar properties.     

Melt polycondensation approach for reduction degradable helical polyester based on l‐cystine

Melt polycondensation approach is developed for new classes of reduction responsive disulfide containing functional polyesters based on l ‐cystine amino acid resources under solvent free process. l ‐Cystine was converted into multi‐functional ester‐urethane monomer and subjected to thermoselective transesterification at 120 °C with commercial diols in the presence of Ti(OBu)₄ to produce polyesters with urethane side chains. The polymers were produced in moderate to high molecular weights and the polymers were found to be thermally stable up to 250 °C. The β‐sheet hydrogen bonding interaction among the side chain urethane unit facilitated the self‐assembly of the polyester into amyloid‐like fibrils. The deprotection of urethane unit into amine functionality modified the polymers into water soluble cationic polyester spherical nanoparticles. The reduction degradation of disulfide bond was studied using DTT as a reducing agent and the high molecular weight polymers chains were found be chopped into low molecular weight oligomers. The cytotoxicity of cationic disulfide nanoparticle was studied in MCF‐7 cells and they were found to be biocompatible and non‐toxic to cells upto 50 μg/mL. The custom designed reduction degradable and highly biocompatible disulfide polyesters from l ‐cystine are useful for futuristic biomedical applications. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2864–2875     

Investigation of various synthetic protocols for self-assembled nanomaterials and their role in catalysis: progress and perspectives

Self-assembly is one of the most used strategies in the controlled synthesis and design of well-organized nanomaterials for various applications in diverse realms namely catalysis, sensors, microelectronics, energy storage, and energy conversion. It is quite common to see reports on the synthesis and design of several self-assembled nanomaterials for the application in the catalysis of various chemical, photochemical, and electrochemical reactions and processes. Nevertheless, a combined overview on the synthetic strategies for self-assembled nanomaterials has not been reported in any form in literature. Owing to the current interest shown and the future significance on the self-assembled nanomaterials, it is highly essential to have such an elaborated review on the progress and perspectives of synthesis of self-assembled nanomaterials and their subsequent application to catalysis of various chemical, photochemical, and electrochemical reactions and processes. In this review, we have highlighted various synthetic methodologies used so far for fabricating the self-assembled nanomaterials that includes Langmuir–Blodgett method, layer-by-layer assembly, amphiphilic (artificial and bio) self-assembly, and template-free approach. Nanomaterials derived from the above mentioned methods in various catalysis reactions are also highlighted in detail with an emphasis on confronts and prospects in the field of materials self-assembling and its concomitant application to catalysis.