Doping and substitution methods are predominantly employed in the synthesis of ceramics to achieve their desired functional properties.We studied the behavior of excessive dopants in addition to an existing stoichiome...Doping and substitution methods are predominantly employed in the synthesis of ceramics to achieve their desired functional properties.We studied the behavior of excessive dopants in addition to an existing stoichiometric composition using a high-throughput continuous compositional spread sputtering method.We paid attention to the possible formation of thermodynamically unstable phases by the addition of an excessive amount of dopants.We showed that even when dopants were added as an additive,they dissolved into the existing lattice due to the benefit of the entropy of mixing.Regardless of excessiveness,all added elements incorporated into the lattice,stabilized by the tolerance factor.We also demonstrated ourfindings exemplarily with lead iron niobate to induce magnetic properties alongside inherent ferroelectricity(M_(S)=10 emu/cm^(3),P_(S)=16μC/cm^(2)).We compare the results from CCS with those from the non-additive solid-state method,leading to a conclusion that the benefit from the entropy of mixing allows foreign elements to substitute for the elements initially residing in the lattice to a degree in compliance with the Goldschmidt tolerance factor.This observation was confirmed by a density functional theory calculation.We anticipate that our study could necessitate intensive research on achieving desired composition through industry-friendly processing.展开更多
Catalytic dehydrogenation represents one of the most effective methods for converting low-carbon hydrocarbons into monoolefins and hydrogen with identical carbon numbers.In this study,microporous(HZSMi)and meso-microp...Catalytic dehydrogenation represents one of the most effective methods for converting low-carbon hydrocarbons into monoolefins and hydrogen with identical carbon numbers.In this study,microporous(HZSMi)and meso-microporous molecular sieves(HZSMu)with a Si/Al atomic ratio of 150,synthesized in the laboratory,were prepared via hydrothermal synthesis.These supports were impregnated with 2.4%Co using the incipient wetness impregnation method and subsequently modified by introducing the metal additives Zr and Sn.Notably,the Co-Sn/HZSMu catalyst exhibited the highest stability,achieving a propylene selectivity of 95.3% within 400 min while maintaining robust activity.A series of characterization analyses reveal that the HZSMu molecular sieve possesses distinctive weaving properties.The synergistic effect between mesopores facilitates the adsorption and activation of reactants while preventing pore blockage,thus promoting the rapid diffusion of reactants on its surface.The incorporation of the metal additive Sn promotes the uniform dispersion of Co,mitigating the occurrence of side reactions and enhancing the catalytic performance and reaction stability of the catalyst.展开更多
基金the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(2021-M1A3B2A01078712)This research was supported by the Korea Institute of Science and Technology Future Resource Program(2E33181)the National Research Foundation of Korea(NRF)grant by the Korea government(No.2021R1A2C2010695,RS-2023-00222719).
文摘Doping and substitution methods are predominantly employed in the synthesis of ceramics to achieve their desired functional properties.We studied the behavior of excessive dopants in addition to an existing stoichiometric composition using a high-throughput continuous compositional spread sputtering method.We paid attention to the possible formation of thermodynamically unstable phases by the addition of an excessive amount of dopants.We showed that even when dopants were added as an additive,they dissolved into the existing lattice due to the benefit of the entropy of mixing.Regardless of excessiveness,all added elements incorporated into the lattice,stabilized by the tolerance factor.We also demonstrated ourfindings exemplarily with lead iron niobate to induce magnetic properties alongside inherent ferroelectricity(M_(S)=10 emu/cm^(3),P_(S)=16μC/cm^(2)).We compare the results from CCS with those from the non-additive solid-state method,leading to a conclusion that the benefit from the entropy of mixing allows foreign elements to substitute for the elements initially residing in the lattice to a degree in compliance with the Goldschmidt tolerance factor.This observation was confirmed by a density functional theory calculation.We anticipate that our study could necessitate intensive research on achieving desired composition through industry-friendly processing.
基金supported by the National Natural Science Foundation of China(Grant No.21968034).
文摘Catalytic dehydrogenation represents one of the most effective methods for converting low-carbon hydrocarbons into monoolefins and hydrogen with identical carbon numbers.In this study,microporous(HZSMi)and meso-microporous molecular sieves(HZSMu)with a Si/Al atomic ratio of 150,synthesized in the laboratory,were prepared via hydrothermal synthesis.These supports were impregnated with 2.4%Co using the incipient wetness impregnation method and subsequently modified by introducing the metal additives Zr and Sn.Notably,the Co-Sn/HZSMu catalyst exhibited the highest stability,achieving a propylene selectivity of 95.3% within 400 min while maintaining robust activity.A series of characterization analyses reveal that the HZSMu molecular sieve possesses distinctive weaving properties.The synergistic effect between mesopores facilitates the adsorption and activation of reactants while preventing pore blockage,thus promoting the rapid diffusion of reactants on its surface.The incorporation of the metal additive Sn promotes the uniform dispersion of Co,mitigating the occurrence of side reactions and enhancing the catalytic performance and reaction stability of the catalyst.
