![]() Nowadays, most researches regarding atomically dispersed M-NC materials are being focused on the characterizations of active sites by using cutting-edge characterization techniques, and developments of new types of metal centers to fit more applicable fields, leaving large space for finely tuning the electronic properties of M-N x moieties via local heteroatom doping. Therefore, it is of great importance and flexibility to tune the catalytic properties of central metal sites by simply manipulating the configuration and functionality of the coordinated N species. Besides of stabilizing metal centers via M-N 4 moiety, the multiple N atoms surrounding metal center also act as bridges for communicating electrons in and out of metal centers and coordinators for responding the feedback from active substrate. Their exceptional catalytic performance, as has been extensively studied, is firstly owing to the isolation presence of metal atom in high unsaturated coordination and high surface energy, secondly thanks to the strong beneficial interaction effects between atomic metal center and conductive substrate. Our work may enlighten relevant studies regarding to accessing improvement on the catalytic performance of atomically dispersed M-NC materials by managing precisely tuned local environments of M-N x moiety.Ītomically dispersed metal-nitrogen-carbon (M-NC) materials have received considerable attention due to excellent catalytic performance that boost sustainable and clean energy utilization technologies such as fuel cells, metal-air batteries, water electrolyzers, CO 2/N 2 fixation. Electrochemical measurements revealed that the Fe-NSC sample exhibited significantly enhanced oxygen reduction reaction performance compared to the S-free Fe-NC material (termed as Fe-NC), showing an excellent onset potential of 1.09 V and half-wave potential of 0.92 V in 0.1 M KOH. Density functional theory simulation suggested that more negative charge density would be localized over Fe-N 4 moiety after S doping, allowing weakened binding capability to *OH intermediates and faster charge transfer from Fe center to O species. ![]() By enabling precisely localized S doping, the electronic structure of Fe-N 4 moiety could be mediated, leading to the beneficial adjustment of absorption/desorption properties of reactant/intermediate on Fe center. ![]() Herein, atomically dispersed Fe-NC material with precise sulfur modification to Fe periphery (termed as Fe-NSC) was synthesized, X-ray absorption near edge structure analysis confirmed the central Fe atom being stabilized in a specific configuration of Fe(N 3)(N–C–S). Immobilizing metal atoms by multiple nitrogen atoms has triggered exceptional catalytic activity toward many critical electrochemical reactions due to their merits of highly unsaturated coordination and strong metal-substrate interaction. ![]()
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