Metal-organic framework(MOF)membranes with an ultra-small pore size(<4Å)have shown great prospects in the highly selective separation of small gas molecules such as hydrogen,but their narrow channels may resul...Metal-organic framework(MOF)membranes with an ultra-small pore size(<4Å)have shown great prospects in the highly selective separation of small gas molecules such as hydrogen,but their narrow channels may result in a low gas permeance.To improve the gas permeance of ultra-microporous MOF membranes,a stable covalent organic framework(COF)with large and uniform pores is doped to construct a binary COF/MOF all-nanoporous composite(ANC)membrane,equivalent to reducing the effective membrane thickness but avoiding the challenging ultra-thin membrane preparation.The COF synthesized by ball milling is combined with a metal gel to form a precursor membrane,which was then transformed to a COF/MOF ANC membrane by treatment with the MOF ligand vapor.A very small amount of solvent has been applied,offering an environmentally-friendly preparation process.Compared with the pristine MOF membrane,the COF/MOF ANC membranes possess a highly improved gas permeance from 22 GPU to 551 GPU with a slight sacrifice of selectivity;this introduces a new strategy to optimize the separation performance of MOF membranes.展开更多
The advancement of wireless communication raises the demand for flexible,high-performance RF antennas for wearable electronics and flexible communication devices.Traditional approaches focused on reducing the thicknes...The advancement of wireless communication raises the demand for flexible,high-performance RF antennas for wearable electronics and flexible communication devices.Traditional approaches focused on reducing the thickness of metal films to enhance flexibility which faces limitations due to the skin effect.Herein,a hybrid graphene-Au nanomembrane is produced by one-step delamination processes to address the limitations of traditional metal films,including flexibility and RF functionality.The graphene-Au nanomembrane features a bond-free van der Waals interface,allowing the Au layer move freely with graphene.This structure mitigates the formation of cracks,enhancing the stretchability to over 14%strain and fatigue resistance.Moreover,this composite overcomes the limitations associated with skin depth,consequently enabling an ultra-thin graphene-Au antenna operating at 8.5 GHz for 5 G communications.We also demonstrate wireless image transmission and electromagnetic stealth.The results underscore the significant impact of the innovative design and materials on flexible wireless technology.展开更多
基金supported by the National Natural Science Foundation of China(Grants No.21501198,21601205 and 21771193)the Taishan Scholar Foundation(ts201511019)+3 种基金the Fundamental Research Funds for the Central Universities(20CX05010A)the PetroChina Innovation Foundation(2019D-5007-0411)the Key Research and Development Projects of Shandong Province(2019JZZY010331)the Shandong Province Natural Science Foundation(ZR2020MB017).
文摘Metal-organic framework(MOF)membranes with an ultra-small pore size(<4Å)have shown great prospects in the highly selective separation of small gas molecules such as hydrogen,but their narrow channels may result in a low gas permeance.To improve the gas permeance of ultra-microporous MOF membranes,a stable covalent organic framework(COF)with large and uniform pores is doped to construct a binary COF/MOF all-nanoporous composite(ANC)membrane,equivalent to reducing the effective membrane thickness but avoiding the challenging ultra-thin membrane preparation.The COF synthesized by ball milling is combined with a metal gel to form a precursor membrane,which was then transformed to a COF/MOF ANC membrane by treatment with the MOF ligand vapor.A very small amount of solvent has been applied,offering an environmentally-friendly preparation process.Compared with the pristine MOF membrane,the COF/MOF ANC membranes possess a highly improved gas permeance from 22 GPU to 551 GPU with a slight sacrifice of selectivity;this introduces a new strategy to optimize the separation performance of MOF membranes.
基金supported by the National Key R&D Program of China(Grant Nos.2022YFB3204800,2022YFB4400100)National Natural Science Foundation of China(Grant Nos.51925208,62122082,52350209)+3 种基金Science and Technology Commission of Shanghai Municipality(Grant No.21JC1406100)CAS Project for Young Scientists in Basic Research(Grant No.YSBR-081)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0670000)City University of Hong Kong Donation Research Grants(Grant nos.DON-RMG 9229021 and 9220061).
文摘The advancement of wireless communication raises the demand for flexible,high-performance RF antennas for wearable electronics and flexible communication devices.Traditional approaches focused on reducing the thickness of metal films to enhance flexibility which faces limitations due to the skin effect.Herein,a hybrid graphene-Au nanomembrane is produced by one-step delamination processes to address the limitations of traditional metal films,including flexibility and RF functionality.The graphene-Au nanomembrane features a bond-free van der Waals interface,allowing the Au layer move freely with graphene.This structure mitigates the formation of cracks,enhancing the stretchability to over 14%strain and fatigue resistance.Moreover,this composite overcomes the limitations associated with skin depth,consequently enabling an ultra-thin graphene-Au antenna operating at 8.5 GHz for 5 G communications.We also demonstrate wireless image transmission and electromagnetic stealth.The results underscore the significant impact of the innovative design and materials on flexible wireless technology.
