调节Co_(3)O_(4)的价电子结构提高硝酸根还原制氨的催化活性  

Modulating the valence electronic structure of Co_(3)O_(4) to improve catalytic activity of electrochemical nitrate-to-ammonia conversion

作　　者：陈文达 陈志达 黄振城 郑黎荣 赵晓娟 胡江涛 曹慧群 李永亮 任祥忠 欧阳晓平 叶盛华 颜学庆 张黔玲 刘剑洪 Wenda Chen;Zhida Chen;Zhencheng Huang;Lirong Zheng;Xiaojuan Zhao;Jiangtao Hu;Huiqun Cao;Yongliang Li;Xiangzhong Ren;Xiaoping Ouyang;Shenghua Ye;Xueqing Yan;Qianling Zhang;Jianhong Liu(Graphene Composite Research Center,College of Chemistry and Environmental Engineering,Shenzhen University,Shenzhen 518060,China;State Key Laboratory of Nuclear Physics and Technology,and Key Laboratory of HEDP of the Ministry of Education,CAPT,Peking University,Beijing 100871,China;Shenzhen Eigen-Equation Graphene Technology Co.,Ltd.,Shenzhen 518000,China;Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;School of Materials Science and Engineering,Xiangtan University,Xiangtan 411105,China)

机构地区：[1]Graphene Composite Research Center,College of Chemistry and Environmental Engineering,Shenzhen University,Shenzhen 518060,China [2]State Key Laboratory of Nuclear Physics and Technology,and Key Laboratory of HEDP of the Ministry of Education,CAPT,Peking University,Beijing 100871,China [3]Shenzhen Eigen-Equation Graphene Technology Co.,Ltd.,Shenzhen 518000,China [4]Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China [5]School of Materials Science and Engineering,Xiangtan University,Xiangtan 411105,China

出　　处：《Science China Materials》2023年第10期3901-3911,共11页中国科学（材料科学（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(11921006);the National Key Research and Development Program of China(2020YFC1909604);Shenzhen Key Projects of Technological Research(JSGG20200925145800001);Shenzhen Science and Technology Program(CJGJZD20210408092801005)。

摘　　要：通过硝酸根电化学还原反应将NO_(3)^(-)转化为NH_(3)是一种有前景的制氨和“绿氢”储存方案.Co_(3)O_(4)对于硝酸根还原析氨反应表现出较高的析氨法拉第效率和稳定性,有望成为理想的催化剂.然而,在Co_(3)O_(4)上发生硝酸根还原反应仍需较高的过电位,从而阻碍了能量转换效率的提升.本文中,我们合成了Cu掺杂Co_(3)O_(4)多孔空心纳米球用作硝酸根还原析氨催化剂.Cu掺杂在保障析氨法拉第效率和稳定性的前提下大幅降低了反应所需的过电位,有效提高了析氨速率.实验和理论分析均表明,Cu掺杂使Co_(3)O_(4)的最高占据态能量上移,缩小了Co_(3)O_(4)的最高占据态与NO_(3)^(-)的最低未占据分子轨道之间的能垒,从而降低了电子从Co_(3)O_(4)向NO_(3)^(-)跃迁所需的过电位,赋予了Cu掺杂Co_(3)O_(4)多孔空心纳米球优异的硝酸根还原析氨电催化活性和耐久性.本研究为纳米材料的电化学性能调控研究提供了新的理论视角.Electrochemical conversion of NO_(3)^(-)to NH_(3) via the nitrate reduction reaction(NO_(3)^(-)RR)is a promising approach for ammonia production and storage of“green hydrogen”.Co_(3)O_(4) has shown satisfactory Faradaic efficiency toward NH_(3)(FE_(NH_(3)))and stability,making it a potential electrocatalyst for the NO_(3)^(-)-to-NH_(3) conversion.However,the high overpotential required for triggering the NO_(3)^(-)RR on Co_(3)O_(4) limits its conversion efficiency.In this study,we synthesized Cu-doped Co_(3)O_(4) porous hollow nanospheres(Cu-Co_(3)O_(4) PHNSs)for NO_(3)^(-)RR.Cu-doping effectively reduced the required overpotential and improved the NH_(3) yield rate on the Co_(3)O_(4) matrix without reducing FE_(NH_(3)) and stability.Both experimental and theoretical analyses demonstrated that Cudoping up-shifted the highest occupied state(HOS)of Co_(3)O_(4),narrowed the energy barrier between the HOS of Co_(3)O_(4) and the lowest unoccupied molecular orbital of NO_(3)^(-),and thus reduced the overpotential required for triggering the electron transfer from Co_(3)O_(4) to NO_(3)^(-),thereby endowing the as-prepared Cu-Co_(3)O_(4) PHNSs with outstanding electrocatalytic activity and durability for the NO_(3)^(-)-to-NH_(3) conversion.This study provides a novel theoretical perspective on the regulation of electrochemical performance.

关 键 词：Co_(3)O_(4) nitrate reduction reaction AMMONIA frontier orbital 

分 类 号：TQ113.2[化学工程—无机化工]