Due to the instability of FeO at temperatures below 843 K,the fuidization reduction pathway of iron ore powder changes with the reduction temperature.Thus,the effect of temperature and reaction pathway interaction on ...Due to the instability of FeO at temperatures below 843 K,the fuidization reduction pathway of iron ore powder changes with the reduction temperature.Thus,the effect of temperature and reaction pathway interaction on the kinetics of fuidization reduction of iron ore powder under low-temperature conditions ranging from 783 to 903 K was investigated to describe the fluidization reduction rate of iron ore powder from three aspects:microstructure change,reaction limiting link,and apparent activation energy of the reaction,exploring their internal correlation.The experimental results revealed that in a temperature range of 783-813 K,the formation of a dense iron layer hindered the internal diffusion of reducing gas,resulting in relatively high gas diffusion resistance.In addition,due to the differences in limiting links and reaction pathways in the intermediate stage of reduction,the apparent activation energy of the reaction varied.The apparent activation energy of the reaction ranged from 23.36 to 89.13 kJ/mol at temperature ranging from 783 to 813 K,while it ranged from 14.30 to 68.34 kJ/mol at temperature ranging from 873 to 903 K.展开更多
Utilizing plasmonic non-noble metal nanoparticles(NPs)for photocatalytic hydrogen evolution reaction is a significant step toward green energy production.However,optimizing the interface between non-noble metal NPs an...Utilizing plasmonic non-noble metal nanoparticles(NPs)for photocatalytic hydrogen evolution reaction is a significant step toward green energy production.However,optimizing the interface between non-noble metal NPs and semiconducting materials in metal-semiconductor composites remains challenging owing to the inevitable surface oxide layers of non-noble metal NPs because the surface oxide layers of non-noble metal NPs can suppress the transfer of photoinduced carriers,leading to poor photocatalytic performance.Herein,we propose a photoinduced interface activation strategy to reduce the number of oxide layers based on a dynamic charge-transfer mechanism under illumination conditions,with Bi NPs and a Ni-based metal-organic framework(MOF)selected as model materials.Under light illumination,the photoinduced charges and plasmonic hot electrons heavily pooled at the interface between the Bi NPs and Ni-MOF,resulting in the reduction of the oxide layer on the surface of Bi,thus attenuating its hindering effect on charge transfer.This phenomenon led to a dynamically enhanced carrier concentration in the Bi/Ni-MOF composite,with an outstanding photocatalytic hydrogen evolution rate of 5822μmol g^(−1)h^(−1)achieved with the composite.The results of this study indicate that our strategy provides a new method for optimizing plasmonic non-noble metal Bi NPs with oxide layers.展开更多
A novel process for synthesizing nano-ceramics powders, named mechanical & therm al activation processing, is discussed in the present paper. It is a processing based on thermal activation in liquid phase (molten ...A novel process for synthesizing nano-ceramics powders, named mechanical & therm al activation processing, is discussed in the present paper. It is a processing based on thermal activation in liquid phase (molten salt) after mechanical activ ation. The nanometer-sized TiC particles (15-20nm) have been synthesized by the method, and analyzed by X-ray diffraction (XRD), transmission electron microscop e (TEM), scanning electron microscopy (SEM) and energy dispersion X-ray (EDX) sp ectroscopy. An interface interaction between liquid (molten salt) and solid (fin al product particles) phases plays a dominating role for the control of product particles size. The mechanism for the formation of nanometer-sized TiC particles has been discussed.展开更多
Nanolayered Cu-Nb composites offer a series of enhanced properties for their use in extreme conditions, e.g. high field magnets and high irradiation resistance. However, the stability of the Cu/Nb heterogeneous interf...Nanolayered Cu-Nb composites offer a series of enhanced properties for their use in extreme conditions, e.g. high field magnets and high irradiation resistance. However, the stability of the Cu/Nb heterogeneous interface needs confirmation under various conditions. In the present work, molecular dynamics simulations were carried out to investigate the interracial behavior under various temperatures with initial stress at the interface. It is found that the interface becomes unstable at simulation temperatures higher than O00 K, resulting in the emission of dislocations and loops within one or more slip systems. The emission process is Found to be thermally-activated, i.e., the higher temperature, the shorter annealing time needed. The present study is believed to assist the experimental synthesis of the Cu-Nb multilayer nanocomposites For multiple applications.展开更多
基金The authors gratefully acknowledge financial support by the National Natural Science Foundation of China-Xinjiang Joint Fund(U2003124)the National Natural Science Foundation of China(No.51974001)the University Outstanding Young Talents Funding Program(No.gxyq2019016).
文摘Due to the instability of FeO at temperatures below 843 K,the fuidization reduction pathway of iron ore powder changes with the reduction temperature.Thus,the effect of temperature and reaction pathway interaction on the kinetics of fuidization reduction of iron ore powder under low-temperature conditions ranging from 783 to 903 K was investigated to describe the fluidization reduction rate of iron ore powder from three aspects:microstructure change,reaction limiting link,and apparent activation energy of the reaction,exploring their internal correlation.The experimental results revealed that in a temperature range of 783-813 K,the formation of a dense iron layer hindered the internal diffusion of reducing gas,resulting in relatively high gas diffusion resistance.In addition,due to the differences in limiting links and reaction pathways in the intermediate stage of reduction,the apparent activation energy of the reaction varied.The apparent activation energy of the reaction ranged from 23.36 to 89.13 kJ/mol at temperature ranging from 783 to 813 K,while it ranged from 14.30 to 68.34 kJ/mol at temperature ranging from 873 to 903 K.
基金supported by the Youth Natural Science Foundation of Shanxi Province(202103021223053)the National Natural Science Foundation of China(NSFC 22271211,22305169)the 1331 Project of Shanxi Province。
文摘Utilizing plasmonic non-noble metal nanoparticles(NPs)for photocatalytic hydrogen evolution reaction is a significant step toward green energy production.However,optimizing the interface between non-noble metal NPs and semiconducting materials in metal-semiconductor composites remains challenging owing to the inevitable surface oxide layers of non-noble metal NPs because the surface oxide layers of non-noble metal NPs can suppress the transfer of photoinduced carriers,leading to poor photocatalytic performance.Herein,we propose a photoinduced interface activation strategy to reduce the number of oxide layers based on a dynamic charge-transfer mechanism under illumination conditions,with Bi NPs and a Ni-based metal-organic framework(MOF)selected as model materials.Under light illumination,the photoinduced charges and plasmonic hot electrons heavily pooled at the interface between the Bi NPs and Ni-MOF,resulting in the reduction of the oxide layer on the surface of Bi,thus attenuating its hindering effect on charge transfer.This phenomenon led to a dynamically enhanced carrier concentration in the Bi/Ni-MOF composite,with an outstanding photocatalytic hydrogen evolution rate of 5822μmol g^(−1)h^(−1)achieved with the composite.The results of this study indicate that our strategy provides a new method for optimizing plasmonic non-noble metal Bi NPs with oxide layers.
基金The project was supported by China Postdoctoral Science Foundation(No.2003034452)National Natural Science Foundation of China(No.50371027).
文摘A novel process for synthesizing nano-ceramics powders, named mechanical & therm al activation processing, is discussed in the present paper. It is a processing based on thermal activation in liquid phase (molten salt) after mechanical activ ation. The nanometer-sized TiC particles (15-20nm) have been synthesized by the method, and analyzed by X-ray diffraction (XRD), transmission electron microscop e (TEM), scanning electron microscopy (SEM) and energy dispersion X-ray (EDX) sp ectroscopy. An interface interaction between liquid (molten salt) and solid (fin al product particles) phases plays a dominating role for the control of product particles size. The mechanism for the formation of nanometer-sized TiC particles has been discussed.
文摘Nanolayered Cu-Nb composites offer a series of enhanced properties for their use in extreme conditions, e.g. high field magnets and high irradiation resistance. However, the stability of the Cu/Nb heterogeneous interface needs confirmation under various conditions. In the present work, molecular dynamics simulations were carried out to investigate the interracial behavior under various temperatures with initial stress at the interface. It is found that the interface becomes unstable at simulation temperatures higher than O00 K, resulting in the emission of dislocations and loops within one or more slip systems. The emission process is Found to be thermally-activated, i.e., the higher temperature, the shorter annealing time needed. The present study is believed to assist the experimental synthesis of the Cu-Nb multilayer nanocomposites For multiple applications.
