采用双向膜相扩散控制原位化学沉积方法,在聚四氟乙烯(PTFE)膜孔道中及膜面上原位化学沉积、生长磁性纳米 Ni 粒子,制得纳米 Ni 粒子/聚合物磁性复合膜。探讨了制备条件对复合膜磁性能的影响,并用 XRD 和SEM 等手段对磁性复合膜的结构...采用双向膜相扩散控制原位化学沉积方法,在聚四氟乙烯(PTFE)膜孔道中及膜面上原位化学沉积、生长磁性纳米 Ni 粒子,制得纳米 Ni 粒子/聚合物磁性复合膜。探讨了制备条件对复合膜磁性能的影响,并用 XRD 和SEM 等手段对磁性复合膜的结构、组成进行了表征。结果表明,复合膜膜孔中及膜表面上均有纳米级 Ni 粒子生成,且膜孔中的 Ni 粒子对复合膜磁性能具有显著影响。展开更多
Electrochemical CO_(2)reduction to produce value-added chemicals and fuels is one of the research hotspots in the field of energy conversion.The development of efficient catalysts with high conductivity and readily ac...Electrochemical CO_(2)reduction to produce value-added chemicals and fuels is one of the research hotspots in the field of energy conversion.The development of efficient catalysts with high conductivity and readily accessible active sites for CO_(2)electroreduction remains challenging yet indispensable.In this work,a reliable poly(ethyleneimine)(PEI)-assisted strategy is developed to prepare a hollow carbon nanocomposite comprising a single-site Ni-modified carbon shell and confined Ni nanoparticles(NPs)(denoted as Ni@NHCS),where PEI not only functions as a mediator to induce the highly dispersed growth of Ni NPs within hollow carbon spheres,but also as a nitrogen precursor to construct highly active atomically-dispersed Ni-Nx sites.Benefiting from the unique structural properties of Ni@NHCS,the aggregation and exposure of Ni NPs can be effectively prevented,while the accessibility of abundant catalytically active Ni-Nx sites can be ensured.As a result,Ni@NHCS exhibits a high CO partial current density of 26.9 mA cm^(-2)and a Faradaic efficiency of 93.0%at-1.0 V vs.RHE,outperforming those of its PEI-free analog.Apart from the excellent activity and selectivity,the shell confinement effect of the hollow carbon sphere endows this catalyst with long-term stability.The findings here are anticipated to help understand the structure-activity relationship in Ni-based carbon catalyst systems for electrocatalytic CO_(2)reduction.Furthermore,the PEI-assisted synthetic concept is potentially applicable to the preparation of high-performance metal-based nanoconfined materials tailored for diverse energy conversion applications and beyond.展开更多
文摘采用双向膜相扩散控制原位化学沉积方法,在聚四氟乙烯(PTFE)膜孔道中及膜面上原位化学沉积、生长磁性纳米 Ni 粒子,制得纳米 Ni 粒子/聚合物磁性复合膜。探讨了制备条件对复合膜磁性能的影响,并用 XRD 和SEM 等手段对磁性复合膜的结构、组成进行了表征。结果表明,复合膜膜孔中及膜表面上均有纳米级 Ni 粒子生成,且膜孔中的 Ni 粒子对复合膜磁性能具有显著影响。
文摘Electrochemical CO_(2)reduction to produce value-added chemicals and fuels is one of the research hotspots in the field of energy conversion.The development of efficient catalysts with high conductivity and readily accessible active sites for CO_(2)electroreduction remains challenging yet indispensable.In this work,a reliable poly(ethyleneimine)(PEI)-assisted strategy is developed to prepare a hollow carbon nanocomposite comprising a single-site Ni-modified carbon shell and confined Ni nanoparticles(NPs)(denoted as Ni@NHCS),where PEI not only functions as a mediator to induce the highly dispersed growth of Ni NPs within hollow carbon spheres,but also as a nitrogen precursor to construct highly active atomically-dispersed Ni-Nx sites.Benefiting from the unique structural properties of Ni@NHCS,the aggregation and exposure of Ni NPs can be effectively prevented,while the accessibility of abundant catalytically active Ni-Nx sites can be ensured.As a result,Ni@NHCS exhibits a high CO partial current density of 26.9 mA cm^(-2)and a Faradaic efficiency of 93.0%at-1.0 V vs.RHE,outperforming those of its PEI-free analog.Apart from the excellent activity and selectivity,the shell confinement effect of the hollow carbon sphere endows this catalyst with long-term stability.The findings here are anticipated to help understand the structure-activity relationship in Ni-based carbon catalyst systems for electrocatalytic CO_(2)reduction.Furthermore,the PEI-assisted synthetic concept is potentially applicable to the preparation of high-performance metal-based nanoconfined materials tailored for diverse energy conversion applications and beyond.
