Using the in-situ liquid cell transmission electron microscopy, the three-stage growth of Pt3Ni-Ni(OH)2 core-shell structures at the gas-liquid interfaces was clearly observed, which consists of(1) a thermodynamically...Using the in-situ liquid cell transmission electron microscopy, the three-stage growth of Pt3Ni-Ni(OH)2 core-shell structures at the gas-liquid interfaces was clearly observed, which consists of(1) a thermodynamically driven Pt3Ni alloy core by the monomer attachment,(2) a nickel(Ni) shell formation due to the depletion of the Pt salt precursor, and(3) the oxidation and of the Ni shell into Ni(OH)2 flakes. We also further observed the nucleation and growth of the Ni(OH)2 flakes on an existing layer either at the middle part or at the step edge. More interestingly, the dynamic transformation among a Pt3Ni alloy, Ni clusters and Ni(OH)2 flakes was also imaged even at a high electron dose rate.展开更多
The construction of highly stable and regular nanoreactors is a major challenge.In this work,we use a facile template protection method to obtain ZIF-67@SiO2(JS) and to encapsulate metal oxide nanoparticles(Co3O4) int...The construction of highly stable and regular nanoreactors is a major challenge.In this work,we use a facile template protection method to obtain ZIF-67@SiO2(JS) and to encapsulate metal oxide nanoparticles(Co3O4) into nanoreactors(SiO2).ZIF-67 crystals provide a cobalt species;SiO2 was first used as a protective layer of ZIF-67 and then as a nanoreactor for metastable metal oxide nanoparticles.On this basis,Co3O4@SiO2 with dodecahedron morphology were synthesized by calcining JS at different tempe ratures,followed by a hydrothermal reaction to obtain Co3(OH)4Si2O5.Subsequently,CoSx and CoP-SiO2 were fabricated through sulfuration and phosphorization.The results in this work show that nanoreactors derived from metal-organic frameworks(MOFs) with a rational structure have broad development prospects.展开更多
基金the National Key Research and Development Program of China(2017YFA0206500)the National Natural Science Foundation of China(21673198,21373008,21621091)。
文摘Using the in-situ liquid cell transmission electron microscopy, the three-stage growth of Pt3Ni-Ni(OH)2 core-shell structures at the gas-liquid interfaces was clearly observed, which consists of(1) a thermodynamically driven Pt3Ni alloy core by the monomer attachment,(2) a nickel(Ni) shell formation due to the depletion of the Pt salt precursor, and(3) the oxidation and of the Ni shell into Ni(OH)2 flakes. We also further observed the nucleation and growth of the Ni(OH)2 flakes on an existing layer either at the middle part or at the step edge. More interestingly, the dynamic transformation among a Pt3Ni alloy, Ni clusters and Ni(OH)2 flakes was also imaged even at a high electron dose rate.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.21671170,21673203)the Topnotch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)+2 种基金Program for New Century Excellent Talents of the University in China(NCET,No.13-0645)the Six Talent Plan(No.2015-XCL-030)Qinglan Project。
文摘The construction of highly stable and regular nanoreactors is a major challenge.In this work,we use a facile template protection method to obtain ZIF-67@SiO2(JS) and to encapsulate metal oxide nanoparticles(Co3O4) into nanoreactors(SiO2).ZIF-67 crystals provide a cobalt species;SiO2 was first used as a protective layer of ZIF-67 and then as a nanoreactor for metastable metal oxide nanoparticles.On this basis,Co3O4@SiO2 with dodecahedron morphology were synthesized by calcining JS at different tempe ratures,followed by a hydrothermal reaction to obtain Co3(OH)4Si2O5.Subsequently,CoSx and CoP-SiO2 were fabricated through sulfuration and phosphorization.The results in this work show that nanoreactors derived from metal-organic frameworks(MOFs) with a rational structure have broad development prospects.