首页|分步负载金属法制备铁钴双金属位点高效氧还原电催化剂

分步负载金属法制备铁钴双金属位点高效氧还原电催化剂

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过渡金属和氮掺杂的碳(M-N-C)由于优异的电催化活性以及较低的生产成本,成为铂基催化剂的替代.然而,目前的M-N-C催化剂通常涉及金属盐、含氮物质和碳载体的结合,在经过热处理和酸洗过程后得到的催化剂在活性位点密度和传质能力上性能不足.采用分步负载金属法制备了Fe、Co双金属掺杂的M-N-C催化剂.利用Zn2+和Co2+的竞争效应,成功合成了小尺寸且均匀的Zn-Co-ZIFs双金属沸石咪唑骨架.随后,在不形成金属团簇的前提下将最大量的Fe原子嵌入C-Zn-Co-ZIFs-H+前体结构中,使其在热解后能产生大量的FeCo—Nx活性位点.这种改进显著增加了FeCo-N-C-2催化剂中Fe活性位点的含量(1.9%,质量分数),并深度优化了其微孔和介孔结构(860 m2·g-1).该催化剂在0.1 mol·L-1 HClO4和0.1 mol·L-1 KOH溶液中,氧还原反应(ORR)活性展现出了0.806 V和0.921 V的半波电位,并分别在50000、45000 s恒定电位测试后保持了91.21%和95.32%的活性.将其组装于质子交换膜燃料电池(PEMFCs)和碱性锌-空气液流电池(ZAFBs)中,峰值功率密度分别达到了746、164 mW·cm-2,显示出优越的性能.
Preparation of high-efficiency iron-cobalt bimetallic site oxygen reduction electrocatalysts by step-by-step metal loading method
Transition metals and nitrogen-doped carbon(M-N-C)have risen to prominence as alternatives to platinum-based catalysts,acclaimed for their superior electrocatalytic activity and comparatively lower production costs.However,current M-N-C catalysts usually involve a combination of metal salts,nitrogen-containing substances and carbon supports.The resulting catalysts after heat treatment and acid washing processes lack sufficient performance in terms of active site density and mass transfer capacity.In this paper,Fe,Co bimetallic doped M-N-C catalysts were prepared by step-by-step metal loading method.Taking advantage of the competitive effect of Zn2+and Co2+,a small-sized and uniform Zn-Co-ZIFs bimetallic zeolite imidazole framework was successfully synthesized.Subsequently,the maximum number of Fe atoms is embedded into the C-Zn-Co-ZIFs-H+precursor structure without forming metal clusters,so that it can generate a large number of FeCo—Nx active sites after pyrolysis.This refinement engenders a substantial augmentation in the Fe active site content of the FeCo-N-C-2 catalyst(1.9%,mass fraction),and a profound optimization of its microporous and mesoporous architecture(860 m2·g-1),culminating in enhanced electrochemical activity and stability.The catalyst exhibited half-wave potentials(E1/2)for oxygen reduction reaction(ORR)of 0.806 V in 0.1 mol·L-1 HClO4 and 0.921 V in 0.1 mol·L-1 KOH,maintaining 91.21%and 95.32%of its activity respectively after 50000,45000 s of a constant voltage test.Moreover,this catalyst has achieved peak power densities of 746 mW·cm-2 in proton exchange membrane fuel cells(PEMFCs)and 164 mW·cm-2 in alkaline zinc-air flow batteries(ZAFBs),demonstrating its superior performance.

catalyststep-by-step metal loading methodiron and cobalt-based dual-metalsiteelectrochemistryoxygen reduction reactionfuel cellszinc-air flow batteries

贾旭东、杨博龙、程前、李雪丽、向中华

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北京化工大学有机无机复合材料国家重点实验室,北京 100029

催化剂 分步负载金属法 铁钴双金属位点 电化学 氧还原反应 燃料电池 锌-空气液流电池

国家重点研发计划国家自然科学基金北京市自然科学基金中国博士后科学基金特别资助项目"双一流"建设项目"双一流"建设项目中国博士后科学基金

2022YFB380750022220102003JL230032023TQ0020XK180301XK1804-02GZC20230199

2024

10.11949/0438-1157.20240073

化工学报
中国化工学会 化学工业出版社

化工学报

CSTPCD北大核心
影响因子：1.26
ISSN：0438-1157
年,卷(期)：2024.75(4)
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