High specific surface area porous graphene grids carbon as anode materials for sodium ion batteries

Although great accomplishments of functional material synthesis have been achieved in sodium ion batteries(SIBs)recently,there are still numerous challenges and problems in preparing carbon-based materials with porous architectures and enough lattice distance for Na^+insertion.Herein we report a templated strategy to synthesize 3D porous graphene girds(PGGs)consisting of several stacking graphene structure with ultrahigh surface area and hierarchical connected structure by employing Ag nanoparticles(NPs).The Ag NPs will regenerate for decreasing the experimental cost,also in line with principles of green chemistry and environmentally friendly strategy.The PGGs obtain advanced specific capacity of160 m A h g^(-1)at current density of 50 m A h g^(-1).Moreover,112 mA h g^(-1)capacity can be gained at 1 A h g^(-1)during 1000 cycles.Due to their porous architecture,ultrahigh surface area and low amorphous graphited structure,PGGs electrode showed the excellent electrochemical performance in high rate capability.

Porous 3D carbon-based materials:An emerging platform for efficient hydrogen production

Due to their unique properties and uninterrupted breakthrough in a myriad of clean energy-related applications,carbon-based materials have received great interest.However,the low selectivity and poor conductivity are two primary difficulties of traditional carbon-based materials(zero-dimensional(0D)/one-dimensional(1D)/two-dimensional(2D)),enerating inefficient hydrogen production and impeding the future commercialization of carbon-based materials.To improve hydrogen production,attempts are made to enlarge the surface area of porous three-dimensional(3D)carbon-based materials,achieve uniform interconnected porous channels,and enhance their stability,especially under extreme conditions.In this review,the structural advantages and performance improvements of porous carbon nanotubes(CNTs),g-C_(3)N_(4),covalent organic frameworks(COFs),metal-organic frameworks(MOFs),MXenes,and biomass-derived carbon-based materials are firstly summarized,followed by discussing the mechanisms involved and assessing the performance of the main hydrogen production methods.These include,for example,photo/electrocatalytic hydrogen production,release from methanolysis of sodium borohydride,methane decomposition,and pyrolysis-gasification.The role that the active sites of porous carbon-based materials play in promoting charge transport,and enhancing electrical conductivity and stability,in a hydrogen production process is discussed.The current challenges and future directions are also discussed to provide guidelines for the development of next-generation high-efficiency hydrogen 3D porous carbon-based materials prospected.

Porous carbon-based thermally conductive materials:Fabrication,functions and applications

The demand for electronic devices has dramatically increased in the past few years.Efficient electronic devices require excellent thermal management systems to extend their operation time and prevent heat accumulation from affecting performance.Carbonaceous materials are considered as one of the ideal thermal management materials due to their excellent physiochemical stability.In addition,since porous-structured carbon materials typically exhibit outstanding thermal conductivity,low density,and large contact area,they have attracted considerable attention from both academia and industry in the last decades.In this review,methods and strategies for the preparation of highly thermally conductive porous carbon-based materials and the factors that influence their thermal conductivity of the materials are summarized.The thermal performance of porous carbonaceous materials fabricated by different approaches and their applications are also discussed.Finally,the potential challenges and strategies for the development and applications of highly thermally conductive porous carbona-ceous materials are discussed.

Function-regeneration of non-porous hydrolyzed-MOF-derived materials

A facile synthetic strategy based on a water-based process is developed for the preparation of metal-organic framework (MOF)-derived materials by revisiting the hydrolyzed non-porous metal-organic frameworks (h-MOF). The poor water stability of MOF has been recognized as key limitations for its commercialization and large-scale applications because the hydrolysis resulted in the complete loss of their functionalities. However, we found that the negative effect of hydrolysis on MOF can be nullified during the heat treatment. As similar to the intact MOF, h-MOF can be used as a precursor for the preparation of MOF-derived materials from porous MOF-derived carbons (MDCs) to MDC@ZnO composites. The property of h-MOF-derived materials is almost equivalent to that of MOF-derived materials. In addition, h-MOF turned the weakness of water instability to the strength of facile water-based process for hybridization. With the demonstration of the hybrid composite between h-MDC@ZnO and reduced graphene oxide (rGO) as a prototype example, it exhibited superior electrochemical performance when evaluated as an electrode material for lithium-ion batteries.

Design strategies for MOF-derived porous functional materials: Preserving surfaces and nurturing pores

MOFs are among the most popular precursors and templates for deriving various porous materials,where the derivatives can inherit a large surface area,abundant active sites for targeted functionalities and a high degree of porosity inherited from their parent MOFs.Those unique structural features make them promising candidates in multiple applications.More interestingly,the structure and properties of these MOF derivatives can be modulated by the choice of the parent MOFs and the design in the conversion process.In this overview,the transformation pathways from MOFs into their porous derivatives,the principles underlying these transformations,and the behavior of the MOF components in the transition process are discussed.Recently,there has been tremendous progress in preserving and enhancing the surface area,the amount of active sites and the level of porosity of the MOF-derived materials for targeted applications,from the perspectives of both customizing the parent MOFs and tailoring the transformation process.To develop the rationally designed MOF-derived materials and thus to elucidate the precursor-process-product correlations,some typical examples of the MOF derivatives applied in electrochemical energy storage and conversion,water treatment,gas sensing,and biomedicine are discussed to demonstrate the effectiveness of the key design strategies.