胶体溶液制备碳纳米管负载钌纳米颗粒的电催化合成氨性能  

Electrocatalytic performances of Ru nanoparticles supported on carbon nanotubes by colloidal solution for synthetic ammonia

作　　者：谢程露 黄贤坤[1,2] 康丽霞 刘永忠 XIE Chenglu;HUANG Xiankun;KANG Lixia;LIU Yongzhong(School of Chemical Engineering and Technology,Xi'an Jiao Tong University;Engineering Research Center of New Energy System Engineering and Equipment,University of Shaanxi Province,Xi'an 710049,Shaanxi,China)

机构地区：[1]西安交通大学化学工程与技术学院 [2]新能源系统工程与装备陕西省高校工程研究中心,陕西西安710049

出　　处：《储能科学与技术》2022年第6期1947-1956,共10页Energy Storage Science and Technology

基　　金：国家自然科学基金(21878240);中央高校基本科研业务费项目(xzd012021035,xhj032021009-05)。

摘　　要：利用胶体溶液制备Ru纳米颗粒。将Ru纳米颗粒负载在碳纳米管上得到用于电化学合成氨的催化剂Ruc/CNT。通过调节Ru胶体溶液的加入量可调整Ruc/CNT上Ru的负载量。借助X射线衍射(XRD)仪、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、接触角测量仪和电化学技术对催化剂进行表征测试。结果表明,通过胶体溶液制备的Ruc/CNT上的钌纳米颗粒缩小至1~5 nm,相比于Ru/CNT上的钌颗粒具有更好的分散性。钌的负载量为2.5%的0.025-Ru_(c)/CNT实现了最高10.98μg/(h·mgcat.)的氨产率及2.18%的法拉第效率,而直接在碳纳米管上回流还原制备的Ru/CNT催化剂仅有5.19μg/(h·mgcat.)的氨产率及0.05%的法拉第效率。通过对照实验对氨的来源进行验证,结果证明氨来源于电化学催化氮气还原过程,钌是催化剂的主要活性位点。钌催化剂颗粒粒径的减小可促进载体与钌纳米颗粒间的电荷转移,削弱反应过程中高能的N≡N三键,提高钌对氮气电化学合成氨的选择性,同时碳纳米管载体的应用为0.025-Ru_(c)/CNT提供足够多的负载位点,分散性更好的钌纳米颗粒能够暴露更多的活性位点,可提升电催化合成氨的性能。Colloidal solution can be used to reduce Ru nanoparticles.The catalyst for electrochemical ammonia synthesis was Ruc/CNT,which was created by supporting Ru nanoparticles on carbon nanotubes(CNT).By varying the volume of the Ru colloid solution,different Ru loadings of the Ruc/CNT can be obtained.Catalyst were characterized using X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscope(TEM),contact angle meter,and electrochemical techniques.The results show that the Ru nanoparticles on Ruc/CNT prepared by colloidal solution are smaller(1-5 nm)and disperse better than those on Ru/CNT.0.025-Ru_(c)/CNT with a Ru load of 2.5%achieved the highest ammonia yield of 10.98μg/(h·mgcat.)and a Faraday efficiency of 2.18%.Nonetheless,Ru/CNT prepared by directly reducing Ru on carbon nanotubes had an ammonia yield of 5.19μg/(h·mgcat.)and a Faraday efficiency of 0.05%.Control experiments confirmed the source of the ammonia.The findings demonstrated that ammonia was produced by an electrochemical catalytic nitrogen reduction reaction.Ru nanoparticles are the catalyst's primary active sites.Reducing the size of Ru particles promotes charge transfer between the carrier and the Ru nanoparticles,weakens the high-energy N≡N triple bonds in the reaction process,and improves ammonia selectivity.CNT application provides sufficient loading sites for 0.025-Ruc/CNT,and Ru nanoparticles with greater dispersion can expose more active sites.As a result,0.025-Ruc/CNT performs better for electrochemical ammonia synthesis.

关 键 词：催化剂 电化学 氮还原 合成氨 选择催化还原 纳米颗粒 

分 类 号：O643.32[理学—物理化学]