厦门大学学报（自然科学版）2025，Vol.64Issue(5)：818-829,12.DOI:10.6043/j.issn.0438-0479.202404029
铜镍合金电催化二氧化碳和硝酸盐合成尿素
Electrocatalytic synthesis of urea from carbon dioxide and nitrate using Cu-Ni alloy
摘要
Abstract
[Objective]The intensive exploitation of fossil fuels has led to excessive carbon dioxide(CO2)emissions,triggering a cascade of environmental challenges.Consequently,the effective utilization of CO2 has garnered widespread research interest.Among various strategies,electrocatalysis offers a viable approach to convert CO 2 into multi-carbon products.Additionally,it is possible within the CO2 reduction electrocatalytic framework to introduce NO 3-for C-N coupling reactions aiming at synthesizing the high-value product,urea.This reaction pathway not only introduces an innovative concept for eco-friendly CO2 conversion but also addresses NO3-pollution from fertilizer-dependent agriculture and industry,paving the way for efficient and clean urea production.Nevertheless,the current state of electrocatalytic C-N coupling for urea synthesis still encounters challenges such as low Faraday efficiency(FE)and lack of control over product selectivity.This work focuses on the study of Cu-Ni catalysts in the electrochemical synthesis of urea via C-N coupling and seeks to enhance the performance of urea electrocatalysis through the creation of alloys techniques.[Methods]Cu and Ni salt precursors were anchored onto a carbon substrate enriched with defects following a rapid carbothermal shock,resulting in the formation of Cu and Ni alloy catalysts.And a series of Cux-Niy/CP alloy catalysts were meticulously crafted by varying the Cu/Ni precursor ratios.The morphology and structure of the catalysts were analyzed using scanning electron microscopy(SEM),transmission electron microscopy(TEM),energy dispersive X-ray spectroscopy(EDS mapping),X-ray powder diffraction(XRD),Raman spectroscopy,and X-ray photoelectron spectroscopy(XPS).The electrocatalytic performance of the catalysts for C-N coupling to urea were tested,and the catalytic mechanism was analyzed by characterizing the electrochemical impedance and electrochemical active surface of the catalysts.[Results]Morphological characterization showed that the catalyst presented nanoparticles of varying sizes with a spherical-like shape,and the distribution of Cu and Ni elements was uniform.Structural characterization confirmed the alloy configuration of the catalyst and revealed that metals existed as oxides on the catalyst surface,which were reduced to metallic states under the tested negative potential,enhancing catalytic activity.Electrocatalytic performance evaluations reveal that the Cu7-Ni3/CP catalyst,with a Cu/Ni precursor ratio of 7∶3,exhibited superior electrocatalytic activity.At a test potential of-0.57 V vs reversible hydrogen electrode(RHE),this catalyst achieved a urea FE of 34.1％and a yield of 98.9 μg/(h·cm2).Compared with reported catalysts,Cu7-Nis/CP catalyst demonstrated commendable selectivity for electrocatalytic C-N coupling to urea.The results of electrochemical impedance spectroscopy and electrochemical active surface area indicated that the addition of metallic Cu helped reduce impedance and facilitated electron transfer,while the addition of metallic Ni enhanced the intrinsic catalytic activity.[Conclusions]By employing a strategy of constructing alloys to compensate for the issues of low selectivity or yield caused by single metal catalysts,the Cu7-Ni3/CP catalyst obtained by adjusting the ratio of metallic Cu and Ni exhibited excellent overall performance in urea synthesis.This work provides an alternative strategy for the recovery of NO 3-and CO2 to produce high value-added chemicals,with promising application prospects.关键词
尿素合成/电催化/C-N偶联/合金纳米颗粒Key words
urea synthesis/electrocatalysis/C-N coupling/alloy nanoparticle分类
化学化工引用本文复制引用
赵佳,徐广阔,蔡湘程,彭丽,杨述良,李军..铜镍合金电催化二氧化碳和硝酸盐合成尿素[J].厦门大学学报（自然科学版）,2025,64(5):818-829,12.基金项目
国家自然科学基金(22373080,22078274) （22373080,22078274）
