The Co 3 O 4 @N doped carbon (Co 3 O 4 @N-C) nanocomposites obtained from metal-organic frameworks (MOFs) possess excellent electrocatalytic ability for oxygen reduction reaction (ORR).Catalysis for oxygen reduction reaction (ORR) is at the heart of key renewable-energy technologies owing to their importance to the variety of energy applications including fuel cells, water splitting and metal-air batteries. [1][2][3] And then the ORR electrocatalysts have been one of the major limiting factors for energy conversion efficiency, cost, and stability of these devices. 1 However, the high cost, limited supply, and weak durability of platinum catalysts are the greatest barriers to large-scale industrial applications. Extensive efforts have been devoted to reducing the amounts of Pt-based catalysts used or replacing them. [4][5][6] The ongoing search for new non-precious-metal catalysts with excellent electrocatalytic performances for ORRs has attracted increasing interest. [7][8][9] In this respect, various kinds of nanostructures, such as metal oxide semiconductors, carbon materials, as well as their composite nanostructures (with the merits of metal oxides and carbon materials), have become popular and are regarded as new candidates for the ORR catalysts. Typically, some anion (S, F, P, N)-doped carbon materials, such as anion-doped graphenes, 10-13 carbon spheres, 14 ordered mesoporous graphitic arrays, 15 carbon nanotubes, 16 and mesoporous carbons, 17 have been reported as the potential ORR catalysts. The mixed valence oxides of transition metals with a spinel structure also show ORR catalytic activity under alkaline conditions. 18 Particularly, the spinel type Co 3 O 4 , in which the Co 2+ and Co 3+ ions occupy the tetrahedral and octahedral sites, respectively, can be used as an ORR electrocatalyst in alkaline

2D Group-VA fluorinated antimonene having an indirect bandgap was synthesized and the nonlinear optical response was studied.

Light-driven micromotor has become one of the research focuses in the past decade, and its motion behavior is usually controlled by light intensity, polarization, and light wavelength. Herein, the light incident angle is utilized to control the motion behavior of silica/Au/pentacene (SiO2/Au/PEN) spherical Janus micromotor. Under tilted irradiation, a single micromotor shows positive phototactic moving behavior without the addition of external chemical fuels, which relies on the photocatalytic reactions and the self-electrophoresis mechanism. Interestingly, when the incident light is tuned to the vertical angle, the SiO2/Au/PEN micromotor stops moving. Similarly, a number of SiO2/Au/PEN micromotors exhibit the same “on–off” motion change, which is dependent on the light incident angle. More interestingly, the “on–off” motion of the SiO2/Au/PEN microparticles under vertical light irradiation results in the formation of the agglomeration with position and size precisely controlled by light. In addition, the resulting aggregation exhibits light-controlled dynamic migration behavior. The incident angle control thus opens up new opportunities for the motion control of the micromotors for diverse applications.

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Although some achievements of constructing chiral metal-organic frameworks (MOFs) with diverse achiral ligands have been made, there is still a lack of full understanding of the origin and formation mechanism of chirality, as well as the reasonable principles for the design and construction of chiral frameworks. The concept of prochirality in organic molecules and complex systems inspires us to explore the synthetic strategy of chiral MOFs based on achiral sources. Here, an achiral compound [Cu(en)][(VO3)2] (1) was isolated in the CuCl2/NH4VO3/en system, while further chiral frameworks [Cu(en)(Im)2][(VO3)2] (2a and 2b) were obtained by the reaction between compound 1 and another achiral ligand Im (ethanediamine = en and imidazole = Im). In the present system, compound 1 has the characteristic of a quasi-plane structure unit. Further reaction of compound 1 and the achiral ligand (Im) induced the formation of chiral Λ/Δ Cu centers, and then a pair of chiral frameworks containing one-dimensional (1D) helical chains was formed. The chiral symmetry breaking phenomenon of compounds 2a and 2b can also be expected and explained based on this kind of prochirality synthetic strategy.