A first-principles study was reported based on density functional theory of hydrogen vacancy,metal dopants,metal dopant-vacancy complex in LiBH4,a promising material for hydrogen storage.The formation of H vacancy and...A first-principles study was reported based on density functional theory of hydrogen vacancy,metal dopants,metal dopant-vacancy complex in LiBH4,a promising material for hydrogen storage.The formation of H vacancy and metal doping in LiBH4 is difficult,and their concentrations are low.The presence of one kind of defect is helpful to the formation of other kind of defect.Based on the analysis of electronic structure,the improvement of the dehydrogenating kinetics of LiBH4 by metal catalysts is due to the weaker bonding of B—H and the new metal-like system,which makes H atom diffuse easily;H vacancy accounts for a trace amount of BH3 release during the decomposing process of LiBH4;metal dopant weakens the strength of B—H bonds,which reduces the dehydriding temperature of LiBH4.The roles of metal and vacancy in the metal dopant-vacancy complex can be added in LiBH4 system.展开更多
The exploration of highly active and durable cathodic oxygen reduction reaction(ORR)catalysts with economical production cost is still the bottleneck to realize the large‐scale commercialization of fuel cells and me...The exploration of highly active and durable cathodic oxygen reduction reaction(ORR)catalysts with economical production cost is still the bottleneck to realize the large‐scale commercialization of fuel cells and metal‐air batteries.Given that carbon support is crucial to the electrocatalysts,and Pt is the best‐known ORR catalyst so far,in this work,we employed a simple impregnation method for synthesizing a kind of defective activated carbon(D‐AC)supported low Pt content electrocatalysts for the ORR.The reduction conditions of the Pt‐containing precursor were firstly optimized,and the influence of the Pt loading amount on the ORR was investigated as well.The results show that the obtained D‐AC@5.0%Pt sample(contains5wt%Pt)has surpassed the commercial Pt/C with20wt%Pt for the ORR in an alkaline solution.In the meantime,it is more stable than the commercial Pt/C.The outstanding ORR performance of the D‐AC@5.0%Pt confirms that both the unique defects in the D‐AC and the introduced Pt particles are indispensable to the ORR.Particularly,m the ORR activity of the synthesized catalysts is superior to most of the reported counterparts,but with much easier preparation methods and lower production cost,making them more advantageous in practical fuel cell applications.展开更多
The development of a high-performing pseudocapacitor requires a comprehensive understanding of electrode materials from the aspects of electron transfer and electrolyte ion adsorption and diffusion.Herein,these factor...The development of a high-performing pseudocapacitor requires a comprehensive understanding of electrode materials from the aspects of electron transfer and electrolyte ion adsorption and diffusion.Herein,these factors are considered over the prototype TiO_(2),and a high pseudocapacitance is achieved via the introduction of various defects,i.e.,oxygen defect(V_(O))and co-doped defect(V_(O)+N_(O)).The study is based on joint explorations of first-principle calculations and the transfer matrix method.Relative to pristine TiO_(2)(300 F g^(-1)),defective TiO_(2) produces pseudocapacitance as high as 1700 F g^(-1).Moreover,defects induce small barriers for electron transmission caused by surface band bending.The climbing image nudged elastic band diffusion of H ions displays a much higher barrier in TiO_(2)-V_(O) than in TiO_(2)-V_(O)+N_(O).Such a result indicates easy H diffusion in the co-doped system.This work provides insights into the adsorption and diffusion of electrolyte ions and the influence of defects on electron transfer.The results are also significant for the design and optimization of electrode materials for the next generation of supercapacitors.展开更多
基金Project (2009AA05Z105) supported by the High-tech Research and Development Program of ChinaProject (20102173) supported by the Natural Science Foundation of Liaoning Province,China
文摘A first-principles study was reported based on density functional theory of hydrogen vacancy,metal dopants,metal dopant-vacancy complex in LiBH4,a promising material for hydrogen storage.The formation of H vacancy and metal doping in LiBH4 is difficult,and their concentrations are low.The presence of one kind of defect is helpful to the formation of other kind of defect.Based on the analysis of electronic structure,the improvement of the dehydrogenating kinetics of LiBH4 by metal catalysts is due to the weaker bonding of B—H and the new metal-like system,which makes H atom diffuse easily;H vacancy accounts for a trace amount of BH3 release during the decomposing process of LiBH4;metal dopant weakens the strength of B—H bonds,which reduces the dehydriding temperature of LiBH4.The roles of metal and vacancy in the metal dopant-vacancy complex can be added in LiBH4 system.
基金financially supported by the Australian Research Council (ARC)
文摘The exploration of highly active and durable cathodic oxygen reduction reaction(ORR)catalysts with economical production cost is still the bottleneck to realize the large‐scale commercialization of fuel cells and metal‐air batteries.Given that carbon support is crucial to the electrocatalysts,and Pt is the best‐known ORR catalyst so far,in this work,we employed a simple impregnation method for synthesizing a kind of defective activated carbon(D‐AC)supported low Pt content electrocatalysts for the ORR.The reduction conditions of the Pt‐containing precursor were firstly optimized,and the influence of the Pt loading amount on the ORR was investigated as well.The results show that the obtained D‐AC@5.0%Pt sample(contains5wt%Pt)has surpassed the commercial Pt/C with20wt%Pt for the ORR in an alkaline solution.In the meantime,it is more stable than the commercial Pt/C.The outstanding ORR performance of the D‐AC@5.0%Pt confirms that both the unique defects in the D‐AC and the introduced Pt particles are indispensable to the ORR.Particularly,m the ORR activity of the synthesized catalysts is superior to most of the reported counterparts,but with much easier preparation methods and lower production cost,making them more advantageous in practical fuel cell applications.
基金financially supported by the National Key Research and Development Program(2016YFB0901600)Tianjin City Distinguished Young Scholar Fund(17JCJQJC45100)+3 种基金the National Natural Science Foundation of China(21975136 and 21573117)Tianjin Key Research and Development Program(18ZXSZSF00060)the Open Funds from the National Engineering Lab for Mobile Source Emission Control Technology(NELMS2018A01)the project of Shenzhen Science,Technology and Innovation Committee(JCYJ20190808151603654)。
文摘The development of a high-performing pseudocapacitor requires a comprehensive understanding of electrode materials from the aspects of electron transfer and electrolyte ion adsorption and diffusion.Herein,these factors are considered over the prototype TiO_(2),and a high pseudocapacitance is achieved via the introduction of various defects,i.e.,oxygen defect(V_(O))and co-doped defect(V_(O)+N_(O)).The study is based on joint explorations of first-principle calculations and the transfer matrix method.Relative to pristine TiO_(2)(300 F g^(-1)),defective TiO_(2) produces pseudocapacitance as high as 1700 F g^(-1).Moreover,defects induce small barriers for electron transmission caused by surface band bending.The climbing image nudged elastic band diffusion of H ions displays a much higher barrier in TiO_(2)-V_(O) than in TiO_(2)-V_(O)+N_(O).Such a result indicates easy H diffusion in the co-doped system.This work provides insights into the adsorption and diffusion of electrolyte ions and the influence of defects on electron transfer.The results are also significant for the design and optimization of electrode materials for the next generation of supercapacitors.
