近年来,工业化的高速推进和化石燃料的大量消耗,不仅造成严重的温室效应,而且加剧了能源危机和环境恶化等问题.电催化CO_(2)还原技术可将温室气体CO_(2)转化为具有经济价值的小分子化合物,且可以耦合间歇性可再生能源(如太阳能、风能、...近年来,工业化的高速推进和化石燃料的大量消耗,不仅造成严重的温室效应,而且加剧了能源危机和环境恶化等问题.电催化CO_(2)还原技术可将温室气体CO_(2)转化为具有经济价值的小分子化合物,且可以耦合间歇性可再生能源(如太阳能、风能、潮汐能等)产生的电力,目前已成为实现碳中和目标最有前景的技术途径之一.然而,由于CO_(2)分子化学惰性较强,需要较高的过电位才能将其活化,导致其转化效率低.铋作为一种无毒无害、价格低廉且具有较高析氢过电位的非贵金属材料,可有效地促进CO_(2)电还原为甲酸.但受质量活性、稳定性和产率的限制,铋基催化剂目前仍难以实现工业化应用.本文采用静电纺丝技术结合热处理方法制备了碳层封装的超小铋纳米颗粒,并用于二氧化碳电还原制甲酸.透射电镜等表征结果表明,铋纳米颗粒均匀地分散于碳纳米纤维中.电化学测试结果表明,在900℃下煅烧2 h制得的Bi/CNFs-900催化剂具有较好的电还原CO_(2)为甲酸的性能.在较宽的电化学窗口内,甲酸的法拉第效率均在90%以上,在-1.20 V vs.RHE的电位下实现了-232.2 mA cm^(-2)的电流密度.该催化剂表现出较高的质量活性(-1.6 A mg-_(Bi)^(-1))和较高的甲酸产率(29.8 mol h^(-1)cm^(-2)g^(-1)),分别是纯铋颗粒质量活性(-0.23 A mg-_(Bi)^(-1))的7.05倍,甲酸产率(4.2 mol h^(-1)cm^(-2)g^(-1))的7.07倍.密度泛函理论计算与原位拉曼光谱结果表明,Bi/CNFs-900能够有效地降低关键中间体*OCHO的吉布斯自由能垒.Bi/CNFs-900具有较好的催化活性和选择性的主要原因为:(1)热解过程中碳纤维对铋纳米颗粒的迁移起到一定限制作用,使得更多的活性位点得以暴露,同时大大降低了金属的实际负载量;(2)铋与周围的碳层存在静电相互作用,可以有效地降低界面电荷的转移电阻,促进电子的快速转移;(3)碳纤维的限域作用也有效地抑制了催化反应过程中Bi纳米颗粒的聚集,使Bi/CNFs-900具有良好的稳定性.综上,本文制得了碳纳米纤维包覆铋纳米颗粒,制备方法简单,经济可行,为设计高性能铋基催化剂并实现二氧化碳电还原制甲酸的应用提供借鉴.展开更多
Electrocatalytic oxygen evolution reaction(OER)is one of the important half reactions of electrocatalytic water splitting.However,the slow kinetic process involving four-electron transfer severely limits its reaction ...Electrocatalytic oxygen evolution reaction(OER)is one of the important half reactions of electrocatalytic water splitting.However,the slow kinetic process involving four-electron transfer severely limits its reaction efficiency,which in turn limits the overall electrocatalytic hydrolysis efficiency.In order to improve the activity of the electrocatalytic OER,researchers mainly update the catalyst from three aspects,that is,increase the conductivity of the electrocatalyst,and the quantity and quality of active sites.Twodimensional(2 D)engineering can effectively reduce the resistance of the materials and greatly increase the number of electrochemically active sites,while heterometal doping,or the bimetal strategy,can improve the quality of active sites via changing the electronic structure of the material.Thus,the combination of the two can enhance the activity of electrocatalytic OER in all three aspects:conductivity,number and quality of active sites.However,there is currently no review on this topic.Therefore,in this review,we summarize the application of bimetallic 2 D materials in electrocatalytic OER from four aspects:the structure,synthesis strategy,catalytic efficiency,and reaction mechanism.展开更多
文摘近年来,工业化的高速推进和化石燃料的大量消耗,不仅造成严重的温室效应,而且加剧了能源危机和环境恶化等问题.电催化CO_(2)还原技术可将温室气体CO_(2)转化为具有经济价值的小分子化合物,且可以耦合间歇性可再生能源(如太阳能、风能、潮汐能等)产生的电力,目前已成为实现碳中和目标最有前景的技术途径之一.然而,由于CO_(2)分子化学惰性较强,需要较高的过电位才能将其活化,导致其转化效率低.铋作为一种无毒无害、价格低廉且具有较高析氢过电位的非贵金属材料,可有效地促进CO_(2)电还原为甲酸.但受质量活性、稳定性和产率的限制,铋基催化剂目前仍难以实现工业化应用.本文采用静电纺丝技术结合热处理方法制备了碳层封装的超小铋纳米颗粒,并用于二氧化碳电还原制甲酸.透射电镜等表征结果表明,铋纳米颗粒均匀地分散于碳纳米纤维中.电化学测试结果表明,在900℃下煅烧2 h制得的Bi/CNFs-900催化剂具有较好的电还原CO_(2)为甲酸的性能.在较宽的电化学窗口内,甲酸的法拉第效率均在90%以上,在-1.20 V vs.RHE的电位下实现了-232.2 mA cm^(-2)的电流密度.该催化剂表现出较高的质量活性(-1.6 A mg-_(Bi)^(-1))和较高的甲酸产率(29.8 mol h^(-1)cm^(-2)g^(-1)),分别是纯铋颗粒质量活性(-0.23 A mg-_(Bi)^(-1))的7.05倍,甲酸产率(4.2 mol h^(-1)cm^(-2)g^(-1))的7.07倍.密度泛函理论计算与原位拉曼光谱结果表明,Bi/CNFs-900能够有效地降低关键中间体*OCHO的吉布斯自由能垒.Bi/CNFs-900具有较好的催化活性和选择性的主要原因为:(1)热解过程中碳纤维对铋纳米颗粒的迁移起到一定限制作用,使得更多的活性位点得以暴露,同时大大降低了金属的实际负载量;(2)铋与周围的碳层存在静电相互作用,可以有效地降低界面电荷的转移电阻,促进电子的快速转移;(3)碳纤维的限域作用也有效地抑制了催化反应过程中Bi纳米颗粒的聚集,使Bi/CNFs-900具有良好的稳定性.综上,本文制得了碳纳米纤维包覆铋纳米颗粒,制备方法简单,经济可行,为设计高性能铋基催化剂并实现二氧化碳电还原制甲酸的应用提供借鉴.
基金supported by Shenzhen Science and Technology Program (JCYJ20200109105803806, SGDX20201103095802006, RCYX20200714114535052,JCYJ20190808150001775,and CYJ20190808143007479)the National Natural Science Foundation of China (U21A20312 and 21975162)Guangdong Basic and Applied Basic Research Foundation (2022B1515120084)。
文摘合理设计铂纳米颗粒尺寸是制备高效氧还原电催化剂的关键.本工作中,我们借助静电纺丝和ZIF-8的双重限域作用合成了超细铂纳米颗粒锚定在多孔碳纳米纤维上的催化材料.低Pt负载(4.2 wt%)的Pt@PCNFs在碱性和酸性电解质中均表现出优异的氧还原反应活性,其质量活性分别为41和51 A gPt^(-1),分别是商业Pt/C催化剂相应值的8倍和10倍.在不同温度的碱性和酸性环境的计时安培试验和加速稳定性实验中, Pt@PCNFs的稳定性均优于Pt/C基准.该催化剂的优异性能可归因于小尺寸的Pt纳米颗粒、丰富多孔的纤维结构、Pt纳米颗粒与N掺杂碳纳米纤维之间的强金属载体相互作用以及碳壳层的保护作用.
基金the National Natural Science Foundation(NNSF)of China(Nos.21975162,51902208,51902209,22172099)the Natural Science Foundation of Guangdong(No.2020A1515010840)Shenzhen Science and Technology Program(Nos.JCYJ20200109105803806,RCYX20200714114535052,RCBS20200714114819161,JCYJ20190808111801674)。
文摘Electrocatalytic oxygen evolution reaction(OER)is one of the important half reactions of electrocatalytic water splitting.However,the slow kinetic process involving four-electron transfer severely limits its reaction efficiency,which in turn limits the overall electrocatalytic hydrolysis efficiency.In order to improve the activity of the electrocatalytic OER,researchers mainly update the catalyst from three aspects,that is,increase the conductivity of the electrocatalyst,and the quantity and quality of active sites.Twodimensional(2 D)engineering can effectively reduce the resistance of the materials and greatly increase the number of electrochemically active sites,while heterometal doping,or the bimetal strategy,can improve the quality of active sites via changing the electronic structure of the material.Thus,the combination of the two can enhance the activity of electrocatalytic OER in all three aspects:conductivity,number and quality of active sites.However,there is currently no review on this topic.Therefore,in this review,we summarize the application of bimetallic 2 D materials in electrocatalytic OER from four aspects:the structure,synthesis strategy,catalytic efficiency,and reaction mechanism.
