富含缺陷的Cu@CuTCNQ复合材料增强电催化硝酸盐还原成氨  

Defect‐rich Cu@CuTCNQ composites for enhanced electrocatalytic nitrate reduction to ammonia

作　　者：周纳 王家志 张宁[1,2] 王志[1,2] 王恒国 黄岗[1,2] 鲍迪 钟海霞 张新波[1,2] Na Zhou;Jiazhi Wang;Ning Zhang;Zhi Wang;Hengguo Wang;Gang Huang;Di Bao;Haixia Zhong;Xinbo Zhang(State Key Laboratory of Rare Earth Resource Utilization,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,Jilin,China;School of Applied Chemistry and Engineering,University of Science and Technology of China,Hefei 230026,Anhui,China;Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education,Faculty of Chemistry,Northeast Normal University,Changchun 130024,Jilin,China)

机构地区：[1]中国科学院长春应用化学研究所稀土资源利用国家重点实验室,吉林长春130022 [2]中国科学技术大学应用化学与工程学院,安徽合肥230026 [3]东北师范大学化学学院,多酸与网格材料化学教育部重点实验室,吉林长春130024

出　　处：《Chinese Journal of Catalysis》2023年第7期324-333,共10页催化学报（英文）

基　　金：国家重点研发计划(2021YFB4000402);国家自然科学基金(52071311,52273277,52072362,21905269);吉林省科技发展计划基金项目(20200201079JC,20220201112GX);中科院青年创新促进会(2021223);国家自然科学基金优秀青年科学基金项目(海外).

摘　　要：将硝酸盐(NO_(3))电化学转化为化学原料和燃料氨(NH3),有助于可持续地缓解当前严峻的能源和环境危机.然而,电催化NO_(3)^(-)还原成NH_(3)(NRA)涉及一个缓慢的八电子转移过程,并与水系中的析氢反应(HER)相竞争,这给开发高选择性的NRA催化剂带来巨大挑战.铜基催化剂是最有应用前景的非贵金属催化剂之一,被广泛用于电化学NO_(3)还原研究.然而,块体铜通常表现出较低的NH_(3)选择性且伴随HER竞争反应.近年来,原位表征技术的快速发展使人们能够观察到电解过程中催化剂的结构演变,并验证原位生成的新的高活性相和局部结构(如应变、空位和晶面)在触发高效催化反应中的作用.研究表明,缺陷位点不仅表现出独特的电子特性,而且可以调节相邻原子的电子结构,通过形成新的协同配位结构,来增强化学吸附和改变中间体能垒从而达到最佳性能,已被广泛应用于氧析出、氧还原和二氧化碳还原等电催化反应中.因此,通过结构演化构建富含铜空位缺陷的催化剂,有望提高NRA的活性和选择性.然而,金属表面缺陷工程对电催化反应的影响研究较少,相关反应机理仍不清楚.因此,阐明空位缺陷对NRA的影响和反应机理对于开发高效NRA催化剂具有重要的指导作用.本文通过简单的原位电化学重构方法构建了一种高效的富含铜空位缺陷的铜@四氰基对苯醌二甲烷铜(Cu@CuTCNQ)复合催化剂,用于常温常压NRA反应.X射线衍射精修结果联合X射线吸收光谱表征表明,成功合成了CuTCNQ络合物,其中单分散的金属离子Cu的氧化态为+1价,与N元素配位成键.采用非原位扫描电子显微镜结合原位电化学拉曼光谱研究了NRA过程中CuTCNQ的形貌和结构演变,C-CN拉曼峰发生蓝移表明从CuTCNQ基底到衍生的Cu位点间的电荷转移作用加强.高分辨透射电子显微镜结合电子顺磁共振表征结果表明,衍生的Cu位点表面存在丰富的Electrochemical conversion of nitrate(NO_(3)^(-))pollutants into chemical feedstock and fuel ammonia(NH_(3))can contribute to sustainable mitigation of the current severe energy and environmental crises.However,the electrocatalytic NO_(3)^(-) reduction to NH_(3)(NRA)involves a sluggish multielectron and proton transfer process that competes with the hydrogen evolution reaction(HER)in aqueous media,imposing great challenges in developing highly selective catalysts for NRA.In this study,we developed a copper and copper‐tetracyanoquinodimethane composite catalyst(Cu@CuTCNQ),which possesses a high density of copper vacancy defects.This catalyst has been proven to be efficient for NRA through an in situ electrochemical reconstruction method.The structural evolution of CuTCNQ during NRA was investigated by in situ Raman spectroscopy,which indicated an accelerated charge transfer from the CuTCNQ substrate to the derived Cu,which facilitated the adsorption activation of NO_(3)^(-).The obtained Cu@CuTCNQ exhibited an excellent catalytic performance for NRA,with a Faradaic efficiency of 96.4%and productivity of 144.8μmol h^(–1)cm^(–2)at−0.6 V vs.a reversible hydrogen electrode,superior to Cu nanoparticle counterparts and most Cu‐based catalysts.Cu vacancy defects and sufficient interfacial charge transfer synergistically optimize the charge distribution of Cu active sites,reduce the energy barrier for NO_(3)^(-) adsorption,and promote deoxidation and hydrogenation processes,thus enhancing NRA and selectivity.

关 键 词：硝酸盐还原 氨合成 铜空位 电催化 电化学重构 

分 类 号：TQ113.2[化学工程—无机化工] TB33[一般工业技术—材料科学与工程]