Chen Shengmei, Liang Xiongyi, Hu Sixia, Li Xinliang, Zhang Guobin, Wang Shuyun, Ma Longtao, Wu Chi-Man Lawrence, Zhi Chunyi, Zapien Juan Antonio
Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, 999077, People's Republic of China.
Sustech Core Research Facilities, Southern University of Science and Technology, 1088 Xueyuan Blvd, Shenzhen, Guangdong, 518055, People's Republic of China.
Nanomicro Lett. 2023 Feb 10;15(1):47. doi: 10.1007/s40820-023-01014-8.
Transition metal-nitrogen-carbon materials (M-N-Cs), particularly Fe-N-Cs, have been found to be electroactive for accelerating oxygen reduction reaction (ORR) kinetics. Although substantial efforts have been devoted to design Fe-N-Cs with increased active species content, surface area, and electronic conductivity, their performance is still far from satisfactory. Hitherto, there is limited research about regulation on the electronic spin states of Fe centers for Fe-N-Cs electrocatalysts to improve their catalytic performance. Here, we introduce TiC MXene with sulfur terminals to regulate the electronic configuration of FeN species and dramatically enhance catalytic activity toward ORR. The MXene with sulfur terminals induce the spin-state transition of FeN species and Fe 3d electron delocalization with d band center upshift, enabling the Fe(II) ions to bind oxygen in the end-on adsorption mode favorable to initiate the reduction of oxygen and boosting oxygen-containing groups adsorption on FeN species and ORR kinetics. The resulting FeN-TiCS exhibits comparable catalytic performance to those of commercial Pt-C. The developed wearable ZABs using FeN-TiCS also exhibit fast kinetics and excellent stability. This study confirms that regulation of the electronic structure of active species via coupling with their support can be a major contributor to enhance their catalytic activity.
过渡金属-氮-碳材料（M-N-Cs），尤其是铁-氮-碳材料（Fe-N-Cs），已被发现具有电活性，可加速氧还原反应（ORR）动力学。尽管人们付出了巨大努力来设计具有更高活性物种含量、表面积和电子导电性的Fe-N-Cs，但其性能仍远不能令人满意。迄今为止，关于调节Fe-N-Cs电催化剂中铁中心的电子自旋态以提高其催化性能的研究还很有限。在此，我们引入具有硫端基的TiC MXene来调节FeN物种的电子构型，并显著提高其对ORR的催化活性。具有硫端基的MXene诱导FeN物种的自旋态转变和Fe 3d电子离域，使d带中心上移，使Fe(II)离子能够以端对端吸附模式结合氧气，有利于引发氧的还原，并促进含氧基团在FeN物种上的吸附和ORR动力学。所得的FeN-TiCS表现出与商业Pt-C相当的催化性能。使用FeN-TiCS开发的可穿戴锌空气电池也表现出快速的动力学和优异的稳定性。这项研究证实，通过与其载体耦合来调节活性物种的电子结构可以是提高其催化活性的一个主要因素。
