As a new frontier in catalysis field,single-atom catalysts(SACs)hold unique electronic structure and high atom utilization,which have displayed unprecedented activity and selectivity toward a wide range of catalytic r...As a new frontier in catalysis field,single-atom catalysts(SACs)hold unique electronic structure and high atom utilization,which have displayed unprecedented activity and selectivity toward a wide range of catalytic reactions.However,many reported SACs are susceptible to Ostwald ripening process in high temperature environment or long-term catalytic application,which will cause sintering and deactivation.This is due to the weak interaction between the metal atom and supports.The regeneration and recycling of deactivated catalysts will greatly increase the time and economic cost of industrial production.Therefore,it is necessary to develop SACs with excellent thermal stability to meet the industrial demands.Here,we discuss the fundamental comprehension of the stability of thermally stable SACs obtained from different synthesis methods.The influences of the speciation of metal centers and coordination environments on thermal stability are summarized.The importance of using novel in situ and operando characterizations to reveal dynamic structural evolution under synthesis and reaction conditions and to identify active sites of thermally stable SACs is highlighted.The mechanistic understanding of the unique role of thermally stable SACs in thermocatalytic application is also discussed.At last,a brief perspective on the remaining challenges and future directions of thermally stable SACs is presented.展开更多
With the availability of the whole genome sequence of Escherichia coli or Corynebacterium glutamicum, strategies for directed DNA manipulation have developed rapidly. DNA manipulation plays an important role in unders...With the availability of the whole genome sequence of Escherichia coli or Corynebacterium glutamicum, strategies for directed DNA manipulation have developed rapidly. DNA manipulation plays an important role in understanding the function of genes and in constructing novel engineering bacteria according to requirement. DNA manipulation involves modifying the autologous genes and expressing the heterogenous genes. Two alternative approaches, using electroporation linear DNA or recombinant suicide plasmid, allow a wide variety of DNA manipulation. However, the over-expression of the desired gene is generally executed via plasmid-mediation. The current review summarizes the common strategies used for genetically modifying E. coli and C. glutamicum genomes, and discusses the technical problem of multi-layered DNA manipulation. Strategies for gene over-expression via integrating into genome are proposed. This review is intended to be an accessible introduction to DNA manipulation within the bacterial genome for novices and a source of the latest experimental information for experienced investigators.展开更多
文摘As a new frontier in catalysis field,single-atom catalysts(SACs)hold unique electronic structure and high atom utilization,which have displayed unprecedented activity and selectivity toward a wide range of catalytic reactions.However,many reported SACs are susceptible to Ostwald ripening process in high temperature environment or long-term catalytic application,which will cause sintering and deactivation.This is due to the weak interaction between the metal atom and supports.The regeneration and recycling of deactivated catalysts will greatly increase the time and economic cost of industrial production.Therefore,it is necessary to develop SACs with excellent thermal stability to meet the industrial demands.Here,we discuss the fundamental comprehension of the stability of thermally stable SACs obtained from different synthesis methods.The influences of the speciation of metal centers and coordination environments on thermal stability are summarized.The importance of using novel in situ and operando characterizations to reveal dynamic structural evolution under synthesis and reaction conditions and to identify active sites of thermally stable SACs is highlighted.The mechanistic understanding of the unique role of thermally stable SACs in thermocatalytic application is also discussed.At last,a brief perspective on the remaining challenges and future directions of thermally stable SACs is presented.
基金supported by the Natural Science Foundation of Jiangsu Province(No.BK20150149)the Fundamental Research Funds for the Central Universities(No.JUSRP51504)the Youth Foundation of Jiangnan University(No.JUSRP115A19),China
文摘With the availability of the whole genome sequence of Escherichia coli or Corynebacterium glutamicum, strategies for directed DNA manipulation have developed rapidly. DNA manipulation plays an important role in understanding the function of genes and in constructing novel engineering bacteria according to requirement. DNA manipulation involves modifying the autologous genes and expressing the heterogenous genes. Two alternative approaches, using electroporation linear DNA or recombinant suicide plasmid, allow a wide variety of DNA manipulation. However, the over-expression of the desired gene is generally executed via plasmid-mediation. The current review summarizes the common strategies used for genetically modifying E. coli and C. glutamicum genomes, and discusses the technical problem of multi-layered DNA manipulation. Strategies for gene over-expression via integrating into genome are proposed. This review is intended to be an accessible introduction to DNA manipulation within the bacterial genome for novices and a source of the latest experimental information for experienced investigators.
