Pulse electrodeposited, morphology controlled organic-inorganic nanohybrids as bifunctional electrocatalysts for urea oxidation

Organic-inorganic nanohybrids with nanoscale architectures and electrocatalytic properties are emerging as a new branch of advanced functional materials. Herein, nanohybrid organic-inorganic nanosheets are grown on carbon paper via a pulse-electrochemical deposition technique. A benzo[2,1,3]selenadiazole-5-carbonyl protected dipeptide BSeFL (BSe = benzoselenadiazole; F = phenylalanine; and L = leucine) cross-linked with Ni2+ ions (Ni-BSeFL) and nickel hydroxide (Ni(OH)2) in a BSeFL/Ni(OH)2 electrode exhibits stable electrocatalytic activity toward urea oxidation. The cross-linked nanosheet morphology of nanohybrids was optimized by controlling the reduction potential during pulse electrodeposition. The BSeFL/Ni(OH)2 (-1.0 V) nanohybrid deposited at -1.0 V provides abundant active sites of Ni3+ with low charge transfer resistance (RCT) and high exchange current density (J0) at the electrocatalytic interface. The nanohybrids with Ni-BSeFL and Ni(OH)2 show low overpotential and superior stability for electrocatalytic urea electro-oxidation. The BSeFL/Ni(OH)2 (-1.0 V) nanohybrid based electrode requires a low potential of 1.30 V (vs. RHE) to acquire a current density of 10 mA cm-2 for the urea oxidation reaction (UOR) in urea containing alkaline solution which is lower than that for water oxidation in alkaline solution (1.49 V vs. RHE). The organic-inorganic nanohybrid BSeFL/Ni(OH)2 (-1.0 V) shows durability over 10 h for oxygen evolution and urea electro-oxidation, thereby confirming the BSeFL/Ni(OH)2 (-1.0 V) nanohybrid-based electrode as an efficient electrocatalyst.

The Importance of Excellent π-π Interactions in Poly(thiophene)s To Reach a High Third-Order Nonlinear Optical Response

Poly(thiophene)s have an inherently large third-order nonlinear optical (TONO) response, but applications are not straightforward due to unoptimized materials. Therefore, several structure-property relationships (molar mass, branching, regioregularity) are investigated to unravel which structural modifications give the highest TONO response. Poly(3-hexylthiophene) with different molar masses, poly[3-(2-ethylhexyl)thiophene] with different molar masses, and random copolymers with different degrees of regioregularity are synthesized and measured by UV-vis spectroscopy and the third harmonic scattering technique. Every structural modification that leads to an increase in π-π interactions in poly(thiophene)s leads to an increase in the TONO response of the material. Therefore, a material with a high molar mass, an unbranched alkyl side chain, and a high regioregularity degree is preferably tested as a promising TONO material.

Crystal structures and investigation of the third-order nonlinear optical properties of four coordination polymers by using the Z-scan technique

Four coordination polymers with different structures are reported. They exhibit different third-order nonlinear optical activities.

The solid state structure and environmental polarization effect of a novel asymmetric azine

Extensive solid state characterization of a novel asymmetric azine and its environmental polarization effect is reported.

Synthesis and characterization of acceptor–donor–acceptor-based low band gap small molecules containing benzoselenadiazole

Acceptor–donor–acceptor-type compounds 5′,5″-(benzo[c][1,2,5]selenadiazole-4,7-diyl)bis(3′-dodecyl-2,2′-bithiophene-5-carbonitrile) (9) and 4,4′-(5,5′-(benzo[c][1,2,5]selenadiazole-4,7-diyl)bis(3-dodecylthiophene-5,2-diyl))dibenzonitrile (10) were designed and synthesized. These compounds differ in terminal positions, compound 9 with a thiophene-containing nitrile group and compound 10 with a phenyl-containing nitrile group. Both compounds have shown good thermal stability and low band gap. The band gaps of compounds 9 and 10 were 1.74 and 1.83 eV, respectively. These results indicate that they are promising materials for use in optoelectronics.