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Single-crystalline hollow CoO nanooctahedra were successfully synthesized by the combination of self-gas-leaching and Ostwald ripening processes through a template-free route. Elaborate microscopy evidence discloses that hollow CoO nanocrystals (NCs) evolve from the channeled CoO NCs, which is an essential intermediate state to construct the hollow structure. Electrochemical measurements indicate that hollow CoO NCs exhibit three times higher specific capacitance than the solid CoO and show excellent cycling stability with the specific capacitance retaining more than 97% after 4500 cycles at a current density of 2 A g−1. Meanwhile, as a catalyst for oxygen evolution reaction and hydrogen production from hydrolysis of sodium borohydride, the hollow and channeled CoO NCs exhibit much better performances than their solid counterparts. The hollow CoO NCs afford a current density of 10 mA cm−2 at a small overpotential of merely 0.375 V and a small Tafel slope of 55 mV decade−1, and they also possess more steady catalytic activity than the channeled CoO. [ABSTRACT FROM AUTHOR]

Two lanthanide MOFs based on 3,3′-((2,3,6,7-tetramethoxyanthracene-9,10-diyl)bis(4,1-phenylene))diacrylic acid (H2LOMe), [Eu(LOMe)1.5(H2O)2]·3.5DMA·2H2O (1) and [Pr(LOMe)(H2O)4]·2.5DMA·3H2O (2) were synthesized under solvothermal conditions. Complex 1 displayed a 2D net with single nodal 44-sql topology, which further formed a 3D supramolecular architecture by strong π…π interaction. Complex 2 featured a 3D open framework with {42·84}-PtS topology. The PL spectrum results showed that 2 has potential application not only in the sensing of small organic molecules, such as DMF and NB, but also in detecting Al3+ and nitroaromatic derivatives. Furthermore, 2 also showed the selective adsorption of CO2 over CH4 and high catalytic activities with the cyanosilylation reaction. [ABSTRACT FROM AUTHOR]

NiPt hollow spheres decorated by Pt nanoparticles were synthesized by a facile wet chemical route through galvanic replacement. In situ STEM imaging and 3D reconstruction were performed to evidence the migration of Pt atoms during catalysis of CO oxidation, providing a practical insight into the structural stability of bimetallic catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Developing the coordinative unsaturation (Fe-N 2) with nitrogen vacancies. • Nitrogen vacancies and Fe-N 2 active site for boosting electrochemical artificial N 2 fixation. • In situ environmental TEM directly visualize N 2 adsorption on FePcTa-PPy. • Fe-N 2 -opp possesses lower overpotential and excellent dynamics stability for ENRR. The construction of definitive correlation between structure and catalytic properties for electrochemical artificial N 2 fixation is still challenging yet significative. Herein, we have explored the coordinative unsaturation (Fe-N 2) in isolated Fe atoms with nitrogen vacancies (V N, which are located at the opposite coordination sites of the Fe atom) on interconnected carbon for electrocatalytic ammonia synthesis. Benefiting from dual active centers (Fe-N 2 and V N) and the spin density on both of them, the novel catalyst exhibits a synergistic improvement of catalytic activity, selectivity, and stability. This work guides the design of the catalyst theoretically and synergistically and combines the advantages of Fe-N 2 with V N structure creation, defect and spin-state engineering introduction toward the concurrent fulfillment of effective N 2 adsorption and activation. We believe our strategy will incite more investigation into designing high-performance catalysts with well-defined coordinative unsaturation single-atom active sites for ambient ammonia synthesis and other energy conversion system. [ABSTRACT FROM AUTHOR]