Ni-doped phenol resin was prepared with 1∶100 mass ratio of Ni（ NO_3）_2·6H_2O to thermosetting phenol resin to optimize the structure and properties of pyrolytic carbon derived from phenol resin and increase i...Ni-doped phenol resin was prepared with 1∶100 mass ratio of Ni（ NO_3）_2·6H_2O to thermosetting phenol resin to optimize the structure and properties of pyrolytic carbon derived from phenol resin and increase its carbon yield. The specimens were cured at 200 ℃ and carbonized under different atmospheres（ carbon-embedded atmosphere and Ar atmosphere） and at different temperatures（ 600,800,1000 and 1200 ℃） for3 h,respectively. The carbon yield was measured. Thermal decomposition characteristics of Ni-doped phenol resin,and the oxidation resistance,phase composition and microstructure of pyrolytic carbon were characterized by differential scanning calorimetry,X-ray diffraction,energy dispersive spectroscopy, scanning electron microscopy and transmission electron microscopy. The results show that the carbon yield of Ni-doped phenol resin carbonized at800 or 1 000 ℃ is increased significantly,compared with that without any dopants. The graphitization degree of pyrolytic carbon structure derived from Ni-doped phenol resin increases with the increase of carbonization temperature. The massive multi-wall carbon nanotubes of 50-100 nm in diameter and of micrometre scale in length are generated at 1000 ℃. Compared with the carbonembedded atmosphere,carbon nanotubes can be more easily generated in Ar atmosphere,resulting in higher carbon yield and degree of crystallinity of the pyrolyticcarbon derived from Ni-doped phenol resin. The oxidation resistance of the pyrolytic carbon derived from Ni-doped phenol resin at 1200 ℃ is improved significantly and its highest oxidation temperature is increased by about 84℃,compared with that from Ni free phenol resin.展开更多
Engineering non-precious metals into nitrogen-doped carbon is employed to improve electrocatalyst activity towards oxygen reduction reaction(ORR). A nickel-doped Co-N/C mesoporous nanopolyhedron is successfully evolut...Engineering non-precious metals into nitrogen-doped carbon is employed to improve electrocatalyst activity towards oxygen reduction reaction(ORR). A nickel-doped Co-N/C mesoporous nanopolyhedron is successfully evoluted from a Ni-doped ZIF-67 precursor. The Ni & Co synergistic N/C catalyst exhibits a half-wave potential of 0.895 V(vs. reversible hydrogen electrode(RHE)) with a diffusion-limiting current density of 6.1 m A cm^(-2)for alkaline ORR at 1600 r min^(-1), which is competitive to commercial Pt/C in terms of cost, methanol tolerance, and long-term stability. In situ surface-enhanced Raman scattering(SERS) study reveals the formation and fast conversion of superoxide ion(O_(2)^(-)) intermediate on the catalyst surface. Density functional theory(DFT) calculations demonstrate the decrease of energy barrier for potential-determining step(O* protonation) by Co-Ni synergy as well as the reduction of adsorption energy on catalyst surface upon nickel doping. The joint results of in situ SERS study and DFT calculations suggest a favourable ORR process on nickel-doped Co-N/C.展开更多
In recent years,the development of an environmentally friendly quantum dots(QDs)embedded luminous solid by a simple method has attracted considerable attention.In this study,semiconductor ZnS QDs were successfully pre...In recent years,the development of an environmentally friendly quantum dots(QDs)embedded luminous solid by a simple method has attracted considerable attention.In this study,semiconductor ZnS QDs were successfully prepared in an inorganic matrix of amorphous glass,which yielded beneficial broadband emission in the long-wavelength region of the visible range.The strong red emission belonged to the defect state energy level of the ZnS QDs,which could be enhanced by incorporation of nickel ions into the fixed matrix to regulate the defects state.The novel material had a small self-absorption,wide excitation and emission ranges,and thus potential applications in light-conversion devices,luminescent solar concentrators,and solar cell cover glasses.展开更多
基金financial supports from the National Natural Science Foundation of China(51174152)National Basic Research Program of China(973 Program)(2012CB722702)
文摘Ni-doped phenol resin was prepared with 1∶100 mass ratio of Ni（ NO_3）_2·6H_2O to thermosetting phenol resin to optimize the structure and properties of pyrolytic carbon derived from phenol resin and increase its carbon yield. The specimens were cured at 200 ℃ and carbonized under different atmospheres（ carbon-embedded atmosphere and Ar atmosphere） and at different temperatures（ 600,800,1000 and 1200 ℃） for3 h,respectively. The carbon yield was measured. Thermal decomposition characteristics of Ni-doped phenol resin,and the oxidation resistance,phase composition and microstructure of pyrolytic carbon were characterized by differential scanning calorimetry,X-ray diffraction,energy dispersive spectroscopy, scanning electron microscopy and transmission electron microscopy. The results show that the carbon yield of Ni-doped phenol resin carbonized at800 or 1 000 ℃ is increased significantly,compared with that without any dopants. The graphitization degree of pyrolytic carbon structure derived from Ni-doped phenol resin increases with the increase of carbonization temperature. The massive multi-wall carbon nanotubes of 50-100 nm in diameter and of micrometre scale in length are generated at 1000 ℃. Compared with the carbonembedded atmosphere,carbon nanotubes can be more easily generated in Ar atmosphere,resulting in higher carbon yield and degree of crystallinity of the pyrolyticcarbon derived from Ni-doped phenol resin. The oxidation resistance of the pyrolytic carbon derived from Ni-doped phenol resin at 1200 ℃ is improved significantly and its highest oxidation temperature is increased by about 84℃,compared with that from Ni free phenol resin.
基金supported by the National Natural Science Foundation of China (No. 21874053)the Science and Technology Development Project of Jilin Province, China (No. 20180414022GH)funding from the Advanced Low Carbon Technology Research and Development Program (ALCA), specially promoted research for innovative nextgeneration batteries (SPRING)。
文摘Engineering non-precious metals into nitrogen-doped carbon is employed to improve electrocatalyst activity towards oxygen reduction reaction(ORR). A nickel-doped Co-N/C mesoporous nanopolyhedron is successfully evoluted from a Ni-doped ZIF-67 precursor. The Ni & Co synergistic N/C catalyst exhibits a half-wave potential of 0.895 V(vs. reversible hydrogen electrode(RHE)) with a diffusion-limiting current density of 6.1 m A cm^(-2)for alkaline ORR at 1600 r min^(-1), which is competitive to commercial Pt/C in terms of cost, methanol tolerance, and long-term stability. In situ surface-enhanced Raman scattering(SERS) study reveals the formation and fast conversion of superoxide ion(O_(2)^(-)) intermediate on the catalyst surface. Density functional theory(DFT) calculations demonstrate the decrease of energy barrier for potential-determining step(O* protonation) by Co-Ni synergy as well as the reduction of adsorption energy on catalyst surface upon nickel doping. The joint results of in situ SERS study and DFT calculations suggest a favourable ORR process on nickel-doped Co-N/C.
基金supported by the National Key Research and Development Project of China(2018YFE0207700)the National Natural Science Foundation of China(NSFC)(61975193,51872270 and U1909211).
文摘In recent years,the development of an environmentally friendly quantum dots(QDs)embedded luminous solid by a simple method has attracted considerable attention.In this study,semiconductor ZnS QDs were successfully prepared in an inorganic matrix of amorphous glass,which yielded beneficial broadband emission in the long-wavelength region of the visible range.The strong red emission belonged to the defect state energy level of the ZnS QDs,which could be enhanced by incorporation of nickel ions into the fixed matrix to regulate the defects state.The novel material had a small self-absorption,wide excitation and emission ranges,and thus potential applications in light-conversion devices,luminescent solar concentrators,and solar cell cover glasses.
