摘要
单原子催化剂(SACs)以近100%的原子利用率以及优秀的催化活性等,在促进多相催化方面受到了广泛关注。然而,由于金属原子在高温下易烧结,SACs的合成仍然具有挑战性。本研究利用熔融盐(MS)提供的强极性环境,制备了以氮掺杂碳为载体的铁基单原子催化剂(Fe SA-NC)。结果表明,Fe SA-NC显示出蜂窝状的多孔形貌,比表面积高达2072 m^(2)·g_(–1),其中Fe元素的重量百分比含量为0.57%。通过球差电镜直接观察到了孤立存在的Fe单原子,并通过X射线吸收精细结构(XAFS)分析确定Fe单原子以Fe-N4配位体形式分散在碳基材料上。Fe SA-NC催化剂在0.1 mol/L KOH溶液中半波电位为0.85 V,极限电流密度为5.79 mA·cm^(–2),优于商业Pt/C催化剂。Fe SA-NC催化剂不仅对ORR四电子途径显示出高选择性(H2O2产率<2%,转移电子数为3.9),同时表现出优秀的抗甲醇性能。
Single atom catalysts(SACs)have emerged as an attractive concept for promoting heterogeneous reactions due to the unique properties,such as high activity and nearly 100%atom utilization.However,the synthesis of SACs remains a challenge due to the sintering of metal atoms at high temperature.In this study,Fe single atom on N doped porous carbon(Fe SA-NC)catalyst was obtained by ultrastrong polarity of molten salt(MS).Fe SA-NC shows honeycomb-like porous morphology and possesses a high specific surface area of 2072 m^(2)·g_(–1).The content of Fe element in Fe SA-NC is 0.57wt%.The isolated Fe atoms are observed by AC HAADF-STEM,and the X-ray absorption fine structure(XAFS)analysis confirms that Fe atoms disperse in the form of Fe-N4 on the carbon substrate.Fe SA-NC shows 0.85 V half-wave potential and 5.79 mA·c^(m–2) maximum current density for ORR in 0.1 mol/L KOH solution.Fe SA-NC displays high selectivity for ORR four electron pathway(H2O2 yield<2%,electron transfer number is 3.9),outstanding stability,and good methanol tolerance.
作者
刘自若
刘炜
郝策
胡金文
史彦涛
LIU Ziruo;LIU Wei;HAO Ce;HU Jinwen;SHI Yantao(Department of Chemistry,School of Chemical Engineering,Dalian University of Technology,Dalian 116024,China)
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2021年第9期943-949,共7页
Journal of Inorganic Materials
基金
国家自然科学基金(51773025)。
关键词
单原子催化剂
多孔
氮掺杂碳
氧还原反应
single atom catalyst
porous
nitrogen-doped carbons
oxygen reduction reaction
