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Two quinoline derivatives, 8-aminoquinoline (8-AQ) and 8-nitroquinoline (8-NQ), have been used as inhibitors to examine their corrosion protection effect on AA5052 aluminium alloy in 3% NaCl solution. The weight-loss and electrochemical measurement have indicated that 8-AQ and 8-NQ play as anodic inhibitor to retard the anodic electrochemical process. SEM/EDS analysis clearly shows that 8-AQ and 8-NQ form a protective film on the AA5052 alloy surface. Density functional theory (DFT) calculation confirmed the formation of strong hybridization between the p-orbital of reactive sites in the inhibitor molecules and the sp-orbital of the Al atom. 8-aminoquinoline and 8-nitroquinoline may be useful as effective corrosion inhibitors for aluminium alloys. [ABSTRACT FROM AUTHOR]

• The B-N dipoles have induced obvious built-in electric fields in 4,12,4-graphyne. • The built-in electric fields result in outstanding electronic, optical properties. • B-N dipoles have brought an obvious piezoelectricity in 4,12,4-graphyne. In present work, B-N pairs as dipole source were introduced into 4,12,4-graphyne. According to the density functional theory (DFT) simulations, the electronic configurations of the doped 4,12,4-graphyne systems were significantly modified owing to the built-in electric fields caused by the B-N dipoles. Different B-N concentrations and arrangements can alter the electronic structure of 4,12,4-graphyne. Consequently, an obvious in-plane piezoelectricity can also be induced. Moreover, the direct band gap can be delicately modulated from 150 meV to 660 meV at PBE level. The B-N dipoles can also greatly enhance the light absorption instead of shifting the absorption region. According to this study, the manipulation of the dipoles in 2D carbon materials is an effective way to acquire the functional materials with some desired physical properties. [ABSTRACT FROM AUTHOR]

The effects of boron (B) and nitrogen (N) substitutions in 4,12,2-graphyne on its geometric structure and mechanical as well as electronic properties have been systematically investigated with the aid of density functional theory (DFT). The trend in the elastic properties of the substituted systems is determined by the doping positions and the type of the dopants. The Bader charge analysis reveals that the N dopant at the sp -site destroys the acetylenic linkage in 4,12,2-graphyne, but instead tends to form a polar bond, or even possibly a charge-shift bond. In particular, an obvious in-plane piezoelectricity is induced by foreign atom substitutions owing to the deformation of the pristine square symmetry. The electron and electronic thermal conductivities are also estimated by performing the Boltzmann's semiclassical transport calculations. Unlabelled Image • N dopant tends to form a polar bond, or even possibly a charge-shift bond at the sp-site in 4,12,2-graphyne. • An observable spin polarization phenomenon can be caused by N-substitution at the sp2-hybridized C2-site. • The directional electron and electronic thermal conductivities can also be induced in 4,12,2-graphyne by B and N dopants. • The B substitution at C3 site provides giant piezoelectric responses. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three ZnAl 2 O 4 surfaces and their activities were theoretically studied. • The stability of ZnAl 2 O 4 decreases in the trend of (1 0 0) > (1 1 1) > (1 1 0). • ZnAl 2 O 4 (1 1 1) is the active surface for syngas to methanol conversion. • Stepwise pathway involving formate moiety dominates initial CO activation. • Activity plot with CO conversion and temperature was revealed. Identifying active site structure and unveiling corresponding reaction pathways are crucial issues to construct compatible reactive components in bifunctional catalysts for direct syngas conversion. Herein, the active surface structure and the reaction mechanism of syngas conversion to bridging intermediate methanol on ZnAl 2 O 4 spinel oxide are systematically investigated by combining density functional theory calculations and microkinetic simulations. The hydroxylated oxygen-rich surfaces of ZnAl 2 O 4 are demonstrated and their stabilities decreases as (1 0 0)-B-1/4H > (1 1 1)-B-3/8H > (1 1 0)-B-1/4H. Four reaction pathways differentiating in the adsorption site of CO and the participation style of H 2 on these surfaces are kinetically compared. We reveal that ZnAl 2 O 4 (1 1 1) is the active surface for syngas conversion; CO bonding on O site is activated more readily in a stepwise way to CH 2 O and the concerted pathway is then followed for CH 2 O to methanol. On ZnAl 2 O 4 (1 0 0) and ZnAl 2 O 4 (1 1 0) surfaces, the Non-Horiuti-Polanyi pathway in which gaseous H 2 reacting directly with CO or CH 2 O becomes kinetically more important. The Zn-O site of ZnAl 2 O 4 (1 1 1) is essential to dissociate H 2 heterolytically and stabilize key intermediate CHO. We show that the reaction rate decreases with the CO conversion, and the simulated reaction rate (~13 s−1) at 8% conversion agrees quite well with the experimental one (~20 s−1) under the typical reaction conditions. The predicted activity plots with temperature and CO conversion highlight the driving essentiality of zeolite component in bifunctional catalysts for syngas conversion. [ABSTRACT FROM AUTHOR]