Under the background of increasing energy crisis and global warming,semiconductor-based photocatalysis has received tremendous attention due to its potential application in green energy production,CO_(2) reduction and...Under the background of increasing energy crisis and global warming,semiconductor-based photocatalysis has received tremendous attention due to its potential application in green energy production,CO_(2) reduction and pollutant degradation.The photocatalytic activity of semiconductors,however,remains low due to issues like fast recombination of photo-generated electron-hole pairs,limited electron mobility,restricted optical absorption or insufficient active sites.Designing appropriate heterojunctions is proved to be a promising method to address most of these issues and thus to improve the photocatalytic performance.In this review,the working mechanism of various heterojunctions is presented systematically.The most recent advances of strategies in designing and preparing efficient heterojunction photocatalysts are further summarized and some perspectives on the future directions in this field are provided.展开更多
The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen e...The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen electrolytic cell equipped with an electrostatic-induction potential-superposed water electrolytic cell that provides a stoichiometric H2-O2 fuel mixture during operation of the vehicle. This generator functions with zero power input, zero matter input and zero emission due to the so-called ＂zero power input＂ electrostatic-to-chemical energy conversion occurring in the electrolytic cell. Here, theoretical simulations were performed to verify the target performance of such generators, assuming a pair of FC （fuel cell） and electrolytic cell stacks, both of which are commercially available.展开更多
An approach was presented to intensify the mixing process. Firstly, a novel concept, the dissipation of mass transfer ability(DMA) associated with convective mass transfer, was defined via an analogy to the heat-work ...An approach was presented to intensify the mixing process. Firstly, a novel concept, the dissipation of mass transfer ability(DMA) associated with convective mass transfer, was defined via an analogy to the heat-work conversion. Accordingly, the focus on mass transfer enhancement can be shifted to seek the extremum of the DMA of the system. To this end, an optimization principle was proposed. A mathematical model was then developed to formulate the optimization into a variational problem. Subsequently, the intensification of the mixing process for a gas mixture in a micro-tube was provided to demonstrate the proposed principle. In the demonstration example, an optimized velocity field was obtained in which the mixing ability was improved, i.e., the mixing process should be intensified by adjusting the velocity field in related equipment. Therefore, a specific procedure was provided to produce a mixer with geometric irregularities associated with an ideal velocity.展开更多
The catalytic effect of electrode materials is one of the most crucial factors for achieving efficient electrochemical energy conversion and storage.Carbon-based metal composites were widely synthesized and employed a...The catalytic effect of electrode materials is one of the most crucial factors for achieving efficient electrochemical energy conversion and storage.Carbon-based metal composites were widely synthesized and employed as electrode materials because of their inherited outstanding properties.Usually,electrode materials can provide a higher capacity than the anticipated values,even beyond the theoretical limit.The origin of the extra capacity has not yet been explained accurately,and its formation mechanism is still ambiguous.Herein,we first summarized the current research progress and drawbacks in energy storage devices(ESDs),and elaborated the role of catalytic effect in enhancing the performance of ESDs as follows:promoting the evolution of the solid electrolyte interphase(SEI),accelerating the reversible conversion of discharge/charge products,and improving the conversion speed of the intermediate and the utilization rate of the active materials,thereby avoiding the shuttling effect.Additionally,a particular focus was placed on the interaction between the catalytic effect and energy storage performance in order to highlight the efficacy and role of the catalytic effect.We hope that this review could provide innovative ideas for designing the electrode materials with an efficient catalytic effect for ESDs to promote the development of this research field.展开更多
文摘Under the background of increasing energy crisis and global warming,semiconductor-based photocatalysis has received tremendous attention due to its potential application in green energy production,CO_(2) reduction and pollutant degradation.The photocatalytic activity of semiconductors,however,remains low due to issues like fast recombination of photo-generated electron-hole pairs,limited electron mobility,restricted optical absorption or insufficient active sites.Designing appropriate heterojunctions is proved to be a promising method to address most of these issues and thus to improve the photocatalytic performance.In this review,the working mechanism of various heterojunctions is presented systematically.The most recent advances of strategies in designing and preparing efficient heterojunction photocatalysts are further summarized and some perspectives on the future directions in this field are provided.
文摘The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen electrolytic cell equipped with an electrostatic-induction potential-superposed water electrolytic cell that provides a stoichiometric H2-O2 fuel mixture during operation of the vehicle. This generator functions with zero power input, zero matter input and zero emission due to the so-called ＂zero power input＂ electrostatic-to-chemical energy conversion occurring in the electrolytic cell. Here, theoretical simulations were performed to verify the target performance of such generators, assuming a pair of FC （fuel cell） and electrolytic cell stacks, both of which are commercially available.
基金Supported by the National Basic Research Program of China("973" Program,No.2012CB720500)the National Natural Science Foundation of China(No.21176171)
文摘An approach was presented to intensify the mixing process. Firstly, a novel concept, the dissipation of mass transfer ability(DMA) associated with convective mass transfer, was defined via an analogy to the heat-work conversion. Accordingly, the focus on mass transfer enhancement can be shifted to seek the extremum of the DMA of the system. To this end, an optimization principle was proposed. A mathematical model was then developed to formulate the optimization into a variational problem. Subsequently, the intensification of the mixing process for a gas mixture in a micro-tube was provided to demonstrate the proposed principle. In the demonstration example, an optimized velocity field was obtained in which the mixing ability was improved, i.e., the mixing process should be intensified by adjusting the velocity field in related equipment. Therefore, a specific procedure was provided to produce a mixer with geometric irregularities associated with an ideal velocity.
基金the National Natural Science Foundation of China(21875221,21890753,22162026,22225204,and U1967215)the National Key Research and Development Program of China(2016YFB0101202)+2 种基金the Youth Talent Support Program of High-Level Talents Special Support Plan in Henan Province(ZYQR201810148)Qiushi Scientific Research Initiation Plan of Zhengzhou University(32213243)the Distinguished Young Scholars Innovation Team of Zhengzhou University(32320275).
文摘The catalytic effect of electrode materials is one of the most crucial factors for achieving efficient electrochemical energy conversion and storage.Carbon-based metal composites were widely synthesized and employed as electrode materials because of their inherited outstanding properties.Usually,electrode materials can provide a higher capacity than the anticipated values,even beyond the theoretical limit.The origin of the extra capacity has not yet been explained accurately,and its formation mechanism is still ambiguous.Herein,we first summarized the current research progress and drawbacks in energy storage devices(ESDs),and elaborated the role of catalytic effect in enhancing the performance of ESDs as follows:promoting the evolution of the solid electrolyte interphase(SEI),accelerating the reversible conversion of discharge/charge products,and improving the conversion speed of the intermediate and the utilization rate of the active materials,thereby avoiding the shuttling effect.Additionally,a particular focus was placed on the interaction between the catalytic effect and energy storage performance in order to highlight the efficacy and role of the catalytic effect.We hope that this review could provide innovative ideas for designing the electrode materials with an efficient catalytic effect for ESDs to promote the development of this research field.
