Zhao Zhendong, Hu Mingzhu, Nie Tiantian, Zhou Wenjun, Pan Bingcai, Xing Baoshan, Zhu Lizhong
State Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310058, China.
Hangzhou Environmental Group, Hangzhou, Zhejiang 310022, China.
Environ Sci Technol. 2023 Mar 21;57(11):4556-4567. doi: 10.1021/acs.est.2c09336. Epub 2023 Mar 9.
Dual-atom catalysts (DACs) are promising candidates for various catalytic reactions, including electrocatalysis, chemical synthesis, and environmental remediation. However, the high-activity origin and mechanism underlying intrinsic activity enhancement remain elusive, especially for the Fenton-like reaction. Herein, we systematically compared the catalytic performance of dual-atom FeCo-N/C with its single-atom counterparts by activating peroxymonosulfate (PMS) for pollutant abatement. The unusual spin-state reconstruction on FeCo-N/C is demonstrated to effectively improve the electronic structure of Fe and Co in the d orbital and enhance the PMS activation efficiency. Accordingly, the dual-atom FeCo-N/C with an intermediate-spin state remarkably boosts the Fenton-like reaction by almost 1 order of magnitude compared with low-spin Co-N/C and high-spin Fe-N/C. Moreover, the established dual-atom-activated PMS system also exhibits excellent stability and robust resistance against harsh conditions. Combined theoretical calculations reveal that unlike unitary Co atom or Fe atom transferring electrons to the PMS molecule, the Fe atom of FeCo-N/C provides extra electrons to the neighboring Co atom and positively shifts the d band of the Co center, thereby optimizing the PMS adsorption and decomposition into a unique high-valent Fe-O-Co species via a low-energy barrier pathway. This work advances a conceptually novel mechanistic understanding of the enhanced catalytic activity of DACs in Fenton-like reactions and helps to expand the application of DACs in various catalytic reactions.
双原子催化剂（DACs）是各种催化反应的有前途的候选者，包括电催化、化学合成和环境修复。然而，其高活性起源以及内在活性增强的机制仍然难以捉摸，尤其是对于类芬顿反应。在此，我们通过活化过一硫酸盐（PMS）用于污染物去除，系统地比较了双原子FeCo-N/C与其单原子对应物的催化性能。结果表明，FeCo-N/C上不寻常的自旋态重构有效地改善了Fe和Co在d轨道中的电子结构，并提高了PMS的活化效率。因此，与低自旋Co-N/C和高自旋Fe-N/C相比，具有中间自旋态的双原子FeCo-N/C显著提高类芬顿反应近1个数量级。此外，所建立的双原子活化PMS系统还表现出优异的稳定性和对苛刻条件的强大抗性。结合理论计算表明，与单一Co原子或Fe原子向PMS分子转移电子不同，FeCo-N/C中的Fe原子向相邻的Co原子提供额外电子，并使Co中心的d带正移，从而通过低能垒途径优化PMS吸附并分解为独特的高价Fe-O-Co物种。这项工作推进了对DACs在类芬顿反应中增强催化活性的全新机理理解，并有助于扩大DACs在各种催化反应中的应用。
