将2D纳米片NiFeP生长在Ketjen Black ECP-600JD炭黑(KB)上制备出花球颗粒状NiFeP/KB电催化剂,再将其与纳米硫颗粒按适当比例均匀混合制备出锂硫电池的正极。这种S/NiFeP/KB正极在0.1C下首次放电比容量为1454.5 mAh/g,循环200次后仍有821...将2D纳米片NiFeP生长在Ketjen Black ECP-600JD炭黑(KB)上制备出花球颗粒状NiFeP/KB电催化剂,再将其与纳米硫颗粒按适当比例均匀混合制备出锂硫电池的正极。这种S/NiFeP/KB正极在0.1C下首次放电比容量为1454.5 mAh/g,循环200次后仍有821.1 mAh/g,在2C下300次循环后比容量为639.9 mAh/g,容量保持率达74.7%;使用NiFeP/KB电催化剂能提高电池中多硫化锂的氧化、还原反应速率,从而改善锂、硫反应动力学。展开更多
Rational design and building of high efficiency,secure and inexpensive electrocatalyst is a pressing demand and performance to promote sustainable improvement of hydrogen energy.The bifunctional electrocatalysts for o...Rational design and building of high efficiency,secure and inexpensive electrocatalyst is a pressing demand and performance to promote sustainable improvement of hydrogen energy.The bifunctional electrocatalysts for oxygen evolution reaction(OER)and hydrogen evolution response(HER)with high catalytic performance and steadiness in the equal electrolyte are extra treasured and meaningful.Herein,a unique three-dimensional(3D)structure electrocatalyst for NiCo_(2)S_(4)growing on the flower-like NiFeP was designed and synthesized in this study.The results show that the flower-like NiCo_(2)S_(4)/NiFeP/NF composite electrocatalyst has large specific surface area,appropriate electrical conductivity,and greater lively websites uncovered in the three-dimensional structure,and affords extraordinary electrocatalytic overall performance for the ordinary water splitting.In alkaline solution,the OER and HER overpotentials of NiCo_(2)S_(4)/NiFeP/NF only need 293 mV and 205 mV overpotential to provide the current densities of 100 mA/cm^(2)and 50 mA/cm^(2),respectively.This high electrocatalytic activity exceeds the catalytic activity of most nickel-iron based electrocatalysts for OER and HER process.Accordingly,the optimized NiCo_(2)S_(4)/NiFeP/NF sample has higher stability(24 h)at 1.560 and 10 mA/cm^(2),which extensively speeds up the overall water splitting process.In view of the above performance,this work offers a fine approach for the further improvement of low fee and excessive effectivity electrocatalyst.展开更多
材料的结构决定其性能。多元镍基或钴基合金在镀态时通常呈非晶态结构,在热处理条件下将发生结构的变化,进而引起性能的变化。主要研究了以下两方面的内容:(1)以柠檬酸钠为络合剂、硼酸为缓冲剂在弱碱性介质中化学沉积Ni_(68.0)Fe_(10.5...材料的结构决定其性能。多元镍基或钴基合金在镀态时通常呈非晶态结构,在热处理条件下将发生结构的变化,进而引起性能的变化。主要研究了以下两方面的内容:(1)以柠檬酸钠为络合剂、硼酸为缓冲剂在弱碱性介质中化学沉积Ni_(68.0)Fe_(10.5)P_(21.5)。采用差示扫描量热(DSC)和X射线衍射(XRD)研究了Ni_(68)Fe_(10.5)P_(21.5)镀层的晶化行为,结果表明,非晶态的镀态镀层在370.0℃下热处理时出现Ni_3P相(I-4),495.0℃下晶化生成FeNi_3相(P_(m3m))。该镀层在镀态时呈圆形颗粒紧密堆积的结构。经过400℃热处理后,镀层晶化生成了许多排列均匀、粒径小于10nm的纳米颗粒;而经过500℃热处理的镀层生成了粒径为20～40 nm的纳米颗粒;经过600℃热处理后晶粒进一步变大,粒径达0.1～0.3μm。在500℃下热处理镀层,随着热处理时间增加,镀层的晶化越完全。据此,通过控制在500℃下热处理时间制备了纳米复合的NiFeP合金。Ni_(68.0)Fe_(10.5)P_(21.5)合金的磁参数(饱和磁化强度、剩余磁化强度和矫顽力)均随着热处理温度的升高而提高;经500℃处理后合金的磁参数达到最大;热处理温度太高,磁参数反而有所降低。发现Ni_(68.0)Fe_(10.5)P_(21.5)合金在500℃下热处理40min时磁参数达到最大;若继续延长热处理时间,则合金的磁参数反而逐渐降低。实验证实,纳米复合的NiFeP合金磁性能最优。(2)以硼氢化钾为还原剂(KBH_4)、乙二胺为稳定剂化学沉积Co-Fe-B。采用差示扫描量热(DSC)和X射线衍射(XRD)研究了Co-Fe-B镀层的晶化行为,结果显示,非晶态的镀态镀层在464.9℃下热处理时晶化为Co_3B and CoFe相。分别采用高分辨扫描电镜和振动样品磁强计研究了热处理温度对镀层微观结构和磁性能的影响,结果表明,随着热处理温度增加到450℃,镀层的饱和磁化强度和矫顽力都增加,并在450℃达到最大值,进一步增加热处理温度,则饱和磁展开更多
基金financially supported by National Key R&D Program of China (No. 2019YFC1907602)National Natural Science Foundation of China (Nos. 51572295, 21273285 and 21003157)
文摘Rational design and building of high efficiency,secure and inexpensive electrocatalyst is a pressing demand and performance to promote sustainable improvement of hydrogen energy.The bifunctional electrocatalysts for oxygen evolution reaction(OER)and hydrogen evolution response(HER)with high catalytic performance and steadiness in the equal electrolyte are extra treasured and meaningful.Herein,a unique three-dimensional(3D)structure electrocatalyst for NiCo_(2)S_(4)growing on the flower-like NiFeP was designed and synthesized in this study.The results show that the flower-like NiCo_(2)S_(4)/NiFeP/NF composite electrocatalyst has large specific surface area,appropriate electrical conductivity,and greater lively websites uncovered in the three-dimensional structure,and affords extraordinary electrocatalytic overall performance for the ordinary water splitting.In alkaline solution,the OER and HER overpotentials of NiCo_(2)S_(4)/NiFeP/NF only need 293 mV and 205 mV overpotential to provide the current densities of 100 mA/cm^(2)and 50 mA/cm^(2),respectively.This high electrocatalytic activity exceeds the catalytic activity of most nickel-iron based electrocatalysts for OER and HER process.Accordingly,the optimized NiCo_(2)S_(4)/NiFeP/NF sample has higher stability(24 h)at 1.560 and 10 mA/cm^(2),which extensively speeds up the overall water splitting process.In view of the above performance,this work offers a fine approach for the further improvement of low fee and excessive effectivity electrocatalyst.
文摘材料的结构决定其性能。多元镍基或钴基合金在镀态时通常呈非晶态结构,在热处理条件下将发生结构的变化,进而引起性能的变化。主要研究了以下两方面的内容:(1)以柠檬酸钠为络合剂、硼酸为缓冲剂在弱碱性介质中化学沉积Ni_(68.0)Fe_(10.5)P_(21.5)。采用差示扫描量热(DSC)和X射线衍射(XRD)研究了Ni_(68)Fe_(10.5)P_(21.5)镀层的晶化行为,结果表明,非晶态的镀态镀层在370.0℃下热处理时出现Ni_3P相(I-4),495.0℃下晶化生成FeNi_3相(P_(m3m))。该镀层在镀态时呈圆形颗粒紧密堆积的结构。经过400℃热处理后,镀层晶化生成了许多排列均匀、粒径小于10nm的纳米颗粒;而经过500℃热处理的镀层生成了粒径为20～40 nm的纳米颗粒;经过600℃热处理后晶粒进一步变大,粒径达0.1～0.3μm。在500℃下热处理镀层,随着热处理时间增加,镀层的晶化越完全。据此,通过控制在500℃下热处理时间制备了纳米复合的NiFeP合金。Ni_(68.0)Fe_(10.5)P_(21.5)合金的磁参数(饱和磁化强度、剩余磁化强度和矫顽力)均随着热处理温度的升高而提高;经500℃处理后合金的磁参数达到最大;热处理温度太高,磁参数反而有所降低。发现Ni_(68.0)Fe_(10.5)P_(21.5)合金在500℃下热处理40min时磁参数达到最大;若继续延长热处理时间,则合金的磁参数反而逐渐降低。实验证实,纳米复合的NiFeP合金磁性能最优。(2)以硼氢化钾为还原剂(KBH_4)、乙二胺为稳定剂化学沉积Co-Fe-B。采用差示扫描量热(DSC)和X射线衍射(XRD)研究了Co-Fe-B镀层的晶化行为,结果显示,非晶态的镀态镀层在464.9℃下热处理时晶化为Co_3B and CoFe相。分别采用高分辨扫描电镜和振动样品磁强计研究了热处理温度对镀层微观结构和磁性能的影响,结果表明,随着热处理温度增加到450℃,镀层的饱和磁化强度和矫顽力都增加,并在450℃达到最大值,进一步增加热处理温度,则饱和磁
