In this work,hierarchical hybrid composites consisting of porous three-dimensional reduced graphene oxide(3D-rGO)skeleton and lamellar boron nitride(BN)/silicon carbide(SiC)coatings are prepared by chemical vapor infi...In this work,hierarchical hybrid composites consisting of porous three-dimensional reduced graphene oxide(3D-rGO)skeleton and lamellar boron nitride(BN)/silicon carbide(SiC)coatings are prepared by chemical vapor infiltration(CVI)process.The graphene framework prepared by 3D printing and frozen self-assembly exhibits a lightweight structure and a perforated conductive network,which extends the transmission path of incident microwaves.The introduced ceramic coatings can effectively tune the impedance matching degree and supply a lossy phase,and the hierarchical structure of the composites enhances the multiple scattering of the incident microwaves.As expected,the 3D-rGO/BN/SiC composites possess an excellent absorbing performance with a minimum reflection loss value of–37.8 dB,and the widest effective absorbing bandwidth(RL<–10 dB)of 5.90 GHz is obtained.The controllable fabrication of composites can provide a guideline for rational design and fabrication of high-performance electromagnetic waves absorbing materials in practical applications.展开更多
Bismuth(Bi)-based nanomaterials are considered as promising electrocatalysts for the electrocatalytic CO_(2) reduction reaction(CO_(2)RR),but it is still challenging to achieve high current density and selectivity in ...Bismuth(Bi)-based nanomaterials are considered as promising electrocatalysts for the electrocatalytic CO_(2) reduction reaction(CO_(2)RR),but it is still challenging to achieve high current density and selectivity in a wide potential window.Herein,Cu-decorated Bi/Bi_(2)O_(3) nanofoam(P-Cu-BiNF)with a 3D porous network structure was prepared for the first time via a simple fast-reduction method.Characterizations indicate that the introduction of Cu can significantly regulate the microstructure and electronic states of Bi/Bi_(2)O_(3).Consequently,the as-prepared P-Cu-BiNF exhibits excellent electrocatalytic performance toward the CO_(2)RR.Remarkably,the faradaic efficiency of formate production can exceed 90% in a wide potential range from -0.78 to -1.08 V.Meanwhile,it can also deliver a high formate partial current density of up to 62.7 mA cm^(-2) at -1.18 V and long-term stability.This work provides a simple but effective way to synthesize advanced Bi-based materials with significantly improved electrocatalytic CO_(2)RR performance.展开更多
Non-precious metal Fe-N-C materials are considered one of the promising substitutes for the Pt/C catalyst toward the oxygen reduction reaction(ORR).However,they still suffer from rapid stability reduction caused by th...Non-precious metal Fe-N-C materials are considered one of the promising substitutes for the Pt/C catalyst toward the oxygen reduction reaction(ORR).However,they still suffer from rapid stability reduction caused by the severe Fenton reaction in the ORR process.Here we report a supramolecular-gel-pyrolysis(SGP)method to design a non-noble CeO_(2)/Ce-N-C composite with a hierarchically porous carbon sheet-network structure.展开更多
基金supported by the National Natural Science Foundation of China(No.51772310)National Natural Science Foundation of China(No.52222202)+3 种基金Chinese Academy of Sciences Key Research Program of Frontier Sciences(No.QYZDYSSWJSC031)Key Deployment Projects of the Chinese Academy of Sciences(No.ZDRW-CN2019-01)Shanghai Sailing Program(No.21YF1454600)Outstanding Chinese and Foreign Youth Exchange Program of China Association of Science and Technology.
文摘In this work,hierarchical hybrid composites consisting of porous three-dimensional reduced graphene oxide(3D-rGO)skeleton and lamellar boron nitride(BN)/silicon carbide(SiC)coatings are prepared by chemical vapor infiltration(CVI)process.The graphene framework prepared by 3D printing and frozen self-assembly exhibits a lightweight structure and a perforated conductive network,which extends the transmission path of incident microwaves.The introduced ceramic coatings can effectively tune the impedance matching degree and supply a lossy phase,and the hierarchical structure of the composites enhances the multiple scattering of the incident microwaves.As expected,the 3D-rGO/BN/SiC composites possess an excellent absorbing performance with a minimum reflection loss value of–37.8 dB,and the widest effective absorbing bandwidth(RL<–10 dB)of 5.90 GHz is obtained.The controllable fabrication of composites can provide a guideline for rational design and fabrication of high-performance electromagnetic waves absorbing materials in practical applications.
基金the National Natural Science Foundation of China(NSFC)(21901246 and 21905278)the Natural Science Foundation of Fujian Province(2019J05158 and 2020J01116).
文摘Bismuth(Bi)-based nanomaterials are considered as promising electrocatalysts for the electrocatalytic CO_(2) reduction reaction(CO_(2)RR),but it is still challenging to achieve high current density and selectivity in a wide potential window.Herein,Cu-decorated Bi/Bi_(2)O_(3) nanofoam(P-Cu-BiNF)with a 3D porous network structure was prepared for the first time via a simple fast-reduction method.Characterizations indicate that the introduction of Cu can significantly regulate the microstructure and electronic states of Bi/Bi_(2)O_(3).Consequently,the as-prepared P-Cu-BiNF exhibits excellent electrocatalytic performance toward the CO_(2)RR.Remarkably,the faradaic efficiency of formate production can exceed 90% in a wide potential range from -0.78 to -1.08 V.Meanwhile,it can also deliver a high formate partial current density of up to 62.7 mA cm^(-2) at -1.18 V and long-term stability.This work provides a simple but effective way to synthesize advanced Bi-based materials with significantly improved electrocatalytic CO_(2)RR performance.
基金supported by the National Natural Science Foundation of China(project no:22275026 and 21805024),the Natural Science Foundation of Chongqing,China(project no:cstc2021jcyj-msxmX0783,cstc2019jscx-msxmX0393 and cstc2018jcyjAX0461)the Scientific and Technological Research Program of Chongqing Municipal Education Commission(project no:KJZD-K202101303,KJQN201901335 and KJQN202001322).
文摘Non-precious metal Fe-N-C materials are considered one of the promising substitutes for the Pt/C catalyst toward the oxygen reduction reaction(ORR).However,they still suffer from rapid stability reduction caused by the severe Fenton reaction in the ORR process.Here we report a supramolecular-gel-pyrolysis(SGP)method to design a non-noble CeO_(2)/Ce-N-C composite with a hierarchically porous carbon sheet-network structure.
