Search

The anomalous Nernst effect (ANE), as a three-dimensional thermoelectric effect in ferromagnetic materials, is expected to break through the limitations of the traditional Seebeck effect, thereby improving thermoelectric conversion efficiency. This study reports an anisotropic anomalous Nernst effect in metallic nickel assembled by the alignment of nanowires. It is found that the ANE voltage varies with the angle to the alignment direction of nanowires within the in-plane of metallic nickel. The ANE voltage reaches 530 nV under a longitudinal temperature difference of 23 K when the magnetic field is applied parallel to the alignment direction of nanowires, which is 143% of its value in the vertical direction. This design concept for anisotropic materials may provide a novel path to enhanced thermoelectric efficiency in ANE-based thermoelectric devices. [ABSTRACT FROM AUTHOR]

In this paper, two morphologies of crystalline Sb2S3 as dumbbell-like Sb2S3 and bundle-like Sb2S3 were synthesized by different phase-transformation of amorphous-to-crystalline, respectively. Different factors such as the variation of the solvent ratio, the surfactant, reaction temperature and reaction time were observed to obtain the key factor influencing the morphology. The bandgap of two Sb2S3 was obtained by diffused reflectance spectra and cyclic voltammetry. The charge separation was characterized by fluorescence spectrum, linear sweep voltammetry, transient photocurrent-time curve and electrochemical impedance spectrum. The results showed that bundle-like Sb2S3 had slightly higher light-harvesting and obvious higher charge separation ability, which was beneficial to the photodegradation of malachite green (MG). The photodegrdation path of MG implied the intermediates generated by bundle-like Sb2S3 were more easily decomposed to the small molecules. Bundle-like Sb2S3 displayed excellent reusability in the photodegradation of MG. Superoxide anion radical (·O2−) and hydroxyl radical (·OH) as the active species contributed to the photodegradation reaction. [ABSTRACT FROM AUTHOR]

Oxygen reduction reaction (ORR) is a crucial reaction for various energy conversion and storage devices, but the sluggish kinetics and the usage of noble metals greatly restrict its practical device applications. In this work, a well-designed high-performance catalyst for ORR was synthesized via a facile one-step Co-MOF carbonization method, in which Co-MOF was prepared using the cobalt acetate tetrahydrate and 2,2′-bipyridyl-5,5′-dicarboxylic acid (H2bpydc) as the only raw materials and H2bpydc as the favorable carbon and nitrogen source for in situ nitrogen doping and metallic cobalt reduction. The resultant 3D mesoporous carbon foam catalyst with embedded Co nanoparticles (CoN-CF) is enriched with nitrogen, which exhibits high specific surface area and abundant N-doping active sites for catalytic ORR. In particular, the optimized CoN-CF-700 sample displays the best catalytic performances including onset potential of 0.94 V, half-wave potential of 0.85 V, long-term durability and superior resistance to methanol poisoning. The demonstrated synthetic strategy provides a new insight into easy-synthesis and high-economy routes for metal-N-C catalysts and a deeper understanding of the effects of microstructures on catalytic mechanisms. [ABSTRACT FROM AUTHOR]

One-dimensional ternary nanostructures, AgCO nanorod cores coated with an intermediate layer of Ag nanoparticles (NPs) and a sheath of conducting polymer polyaniline (PANI), AgCO/Ag/PANI composite nanorods (CNRs), were successfully prepared via a facile two-step method. Ag NPs were first uniformly anchored onto the AgCO nanorods to form binary AgCO/Ag CNRs with an in situ visible-light-induced reduction strategy, and then the AgCO/Ag CNRs were coated with PANI of different contents through a simple chemisorption approach. The as-obtained hybrids exhibit significantly enhanced photoelectrochemical current response and photoactivity in degrading methyl orange under visible-light illumination ( λ > 420 nm). The improved photoactivity was found to be related to the intermediate Ag between AgCO and PANI which facilitates the separation efficiency of photogenerated carriers, and an optimal weight percent of 2.0% PANI was observed. The origin of enhanced photoactivity was further investigated by a radical-trapping test, and a Z-scheme mechanism was proposed to explain the charge separation behaviors. [ABSTRACT FROM AUTHOR]