CuPc/FeNC双组分催化剂协同催化硝酸盐转化为氨  

Synergistic catalytic conversion of nitrate into ammonia on copper phthalocyanine and FeNC two‐component catalyst

作　　者：王毅[1,2] 王硕 付云凡 桑佳琪 臧一鹏 魏鹏飞 李合肥 汪国雄 包信和[1] Yi Wang;Shuo Wang;Yunfan Fu;Jiaqi Sang;Yipeng Zang;Pengfei Wei;Hefei Li;Guoxiong Wang;Xinhe Bao(State Key Laboratory of Catalysis,Dalian National Laboratory for Clean Energy,iChEM(Collaborative Innovation Center of Chemistry for Energy Materials),Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,Liaoning,China;College of Energy,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院大连化学物理研究所,能源材料化学协同创新中心,大连洁净能源国家实验室,催化基础国家重点实验室,辽宁大连116023 [2]中国科学院大学能源学院,北京100049

出　　处：《Chinese Journal of Catalysis》2024年第1期104-113,共10页催化学报（英文）

基　　金：国家重点研发项目(2022YFA1504000);国家自然科学基金(22125205,92045302);中央高校基础研究经费(20720220008),洁净能源国家实验室基金(DNL202007,DNL201923).

摘　　要：氨(NH_(3))作为重要的化学品和能源储存介质,需求量与日俱增.本文旨在通过电化学硝酸根还原反应(NO_(3)^(−)RR),将NO_(3)^(−)转化为NH3,不仅解决了NO_(3)^(−)引起的环境污染问题,又可以满足对NH_(3)的迫切需求.然而,NO_(3)^(−)RR涉及多个电子和质子转移过程,其中,NO_(2)^(−)是NO_(3)^(−)活化转化和深度还原合成NH_(3)的重要中间体.酞菁铜(CuPc)能够高效地活化转化NO_(3)^(−)为NO_(2)^(−),但在低过电位时无法有效地将NO2−还原为NH3,难以获得较高的氨法拉第效率(FENH3)和分电流密度.而氮配位的铁单原子催化剂(FeNC)则有较好的NO_(2)^(−)吸附活化特性.因此,利用双组分催化剂之间的协同作用以实现高效NO_(3)^(−)RR的活性和选择性是本文的主要研究思路.本文设计了CuPc/FeNC串联催化剂,利用CuPc和FeNC对NO_(3)^(−)和NO_(2)^(−)的吸附活化能力的差异,实现了高效的协同催化转化.X射线衍射、高角环形暗场扫描透射电镜、X射线光电子能谱及X射线吸收谱结果表明,FeNC催化剂中Fe原子均匀分布于ZIF-8热解后的基底.通过将FeNC和CuPc负载于气体扩散电极,在流动电解池中完成NO_(3)^(−)RR.CuPc/FeNC催化剂在较低电势区间中能够实现接近100%的NH3法拉第效率,同时在−0.57 V vs.RHE时达到273 mA cm–2的NH3分电流密度,并且在整个电势范围内有效地抑制了NO_(2)^(–)聚集.与单组分催化剂CuPc和FeNC对比结果表明,在−0.53 V vs.RHE时,CuPc/FeNC催化剂表现出较高的FE(NH_(3))/FE(NO_(2)^(−))比值,是CuPc催化剂的50倍;同时CuPc/FeNC催化剂上NH3分电流密度是FeNC催化剂的1.5倍.进一步研究了NO_(3)^(–)RR中的串联反应机制,其中FeNC催化剂表现出较高的NO_(2)^(–)RR活性,并且有效抑制了析氢反应.此外,CuPc/FeNC催化剂和FeNC催化剂在NO_(2)^(−)RR中表现出类似的NH3分电流密度,这表明在NO_(3)^(−)RR中,CuPc/FeNC催化剂性能的提高来源于FeNC位点能够Cu-based catalysts have been extensively studied to enhance the performance of the electrochemical nitrate reduction reaction(NO_(3)^(−)RR),while it is still a challenge to balance high ammonia(NH_(3))current density and Faradaic efficiency.Here,we incorporated nitrogen coordinated iron single atom catalyst(FeNC)with copper phthalocyanine(CuPc),denoted as CuPc/FeNC,for NO_(3)^(−)RR.Compared with the two individual catalysts,this two-component catalyst increases NH3 Faradaic efficiency and current density at low overpotentials,achieves efficient synergistic catalytic conversion.Experiments and theoretical calculations reveal that the enhanced electrochemical performance of CuPc/FeNC catalyst comes from the tandem process,in which NO_(2)^(‒) is produced on CuPc and then transferred to FeNC and further reduced to NH3.In this exceptional tandem catalyst system,an outstanding NH_(3) Faradaic efficiency close to 100%was achieved at potentials greater than−0.35 V vs.RHE,coupled with a peak NH_(3) partial current density of 273 mA cm^(‒2)at−0.57 V vs.RHE,effectively suppressing NO_(2)^(‒)production across the entire potential range.This strategy provides a design platform for the continued advancement of NO_(3)^(‒)RR catalysts.

关 键 词：硝酸根电化学还原为氨 协同催化转化 串联催化 双组分催化剂 动态现场原位表征 

分 类 号：O643.36[理学—物理化学]