Axial nitrogen-coordination engineering over Fe-Nx active species for enhancing Fenton-like reaction performance

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-02, Vol.454, p.140382, Article 140382
• Main Authors: Liu, Fenli, Ren, Yujing, Duan, Jianglin, Deng, Pengcheng, Lu, Jianyu, Ge, Huibin, Liu, Xin, Xia, Qixing, Qi, Haifeng, Yang, Na, Qin, Yong
• Format: Article
• Language: English
• Subjects: Axial coordination engineering; Fe-N5 site; Fenton-like reaction; Single-atom catalyst; Structure-performance relationship
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.140382

Development of axial nitrogen-coordination engineering strategy. Regulation of single-atom catalyst coordination environment. Fenton-like reaction performance enhancement. Structure-performance relationship establishment. [Display omitted] •Axial coordination regulation strategy of single-atom catalyst is developed.•Intrinsic catalytic activities of Fe-Nx single-atom sites are identified.•Axial N-coordination enhances Fenton-like reaction performance over Fe-N5 species.•Role of axial N-coordination for weakening H2O adsorption is revealed. Activating hydrogen peroxide (H2O2) to produce hydroxyl radical (•OH) (Fenton-like process) is of great importance in heterogeneous catalytic oxidations. However, most of transition metal nano-catalysts as well as recently reported carbon supported Fe-N4 single atom catalysts (SACs) suffer from unsatisfactory catalytic performance. Herein, a novel Fe1/C3N4 SAC with Fe-N5 active site was constructed. Using this SAC, the electron/structure-symmetry of Fe-N4 site can be broken by axial nitrogen-coordination, which transforms less active Fe-N4 species into highly active Fe-N5 species in Fenton-like reaction. Specifically, Fe-N5 site exhibits an unprecedented activity for 3,3′,5,5′-tetramethylbenzidine oxidation, which is at least one order of magnitude more active than reported Fe-N4/C SACs. Mechanism studies reveal that the unique role of axial nitrogen-coordination over Fe-Nx sites is to change the adsorption behavior of H2O over Fe-N5 site without influencing H2O2 activation. This discovery provides a new approach for rationally designing efficient catalysts in Fenton-like reactions.