The cleavage and functionalization of recalcitrant carbon─carbon bonds is highly challenging but represents a very powerful tool for value-added transformation of feedstock chemicals. Here, an enzyme-mimic iron single-atom catalyst (SAC) bearing iron (III) nitride (FeN 3 ) motifs was prepared and found to be robust for cleavage and cyanation of carbon–carbon bonds in secondary alcohols and ketones. High nitrile yields are obtained with a wide variety of functional groups. The prepared FeN 3 -SAC exhibits high enzyme-like activity and is capable of generating a dioxygen-to-superoxide radical at room temperature, while the commonly reported FeN 4 -SAC bearing FeN 4 motifs was inactive. Density functional theory (DFT) calculation reveals that the activation energy of dioxygen activation and the activation energy of the rate-determining step of nitrile formation are lower over FeN 3 -SAC than FeN 4 -SAC. In addition, DFT calculation also explains the catalyst’s high selectivity for nitriles.
Hongjin Xue,Yunqian Li,Xinyu Ma,Qi Zhang,Junkai Zhu,Xiaoli Ni,Jianfeng Qiu,Zhengjun Li,Zhen Mu
Psoriasis is a chronic skin condition with significant unmet medical needs, characterized by high levels of reactive oxygen species (ROS) and accompanying oxidative stress. In this study, we developed a novel single-atom iron nanozyme (Fe-N 3 ), designed to mimic natural antioxidant enzymes, for the effective treatment of psoriasis. By optimizing the local coordination environment of Fe atoms, Fe-N 3 demonstrated superior superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APx), and glutathione peroxidase (GPx)-like activities compared to Fe-N 4 . These properties enable efficient ROS scavenging and oxidative stress alleviation. Theoretical analyses revealed that Fe-N 3 possesses lower energy barriers for ROS decomposition, explaining its superior catalytic performance. Furthermore, in vitro and in vivo experiments have demonstrated that Fe-N 3 nanozyme exhibited remarkable therapeutic effects with extremely low cytotoxicity, effectively inhibiting pathological epidermal proliferation, downregulating key inflammatory factors, and reducing the expression levels of psoriasis-associated pathway proteins. This work highlights the promise of single-atom nanozymes in the curing of inflammatory skin diseases, advancing the transformative role of nanotechnology in biomedicine.
Haidong Yang,Yang Liu,Yutong Luo,Shiqing Lu,Bitao Su,Jiantai Ma
Electrocatalytic nitrogen reduction reaction (NRR) represents a highly promising process to ammonia synthesis for artificial N2 fixation. However, the yield rate for NH3 production and Faradaic efficiency (FE) are still low, which greatly hinder its widespread applications. Until now, although a variety of catalysts, including single-atom catalysts, have been developed for NRR in the pursuit of suppressing hydrogen evolution reaction (HER) and the corresponding higher FE, the limited NH3 yield rate makes them uncompetitive for the synthesis of ammonia. Herein, we report a Fe single-atom catalyst anchoring on a nitrogen-doped carbon substrate (Fe SAC/N–C) as a highly efficient NRR catalyst. The catalyst achieves a high FE of 39.6% in 0.1 M KOH under room temperature, particularly a dramatically enhanced NH3 yield rate of 53.12 μgNH3 h–1 mgcat–1. The isotopic labeling (15N2) experiment confirms that the NH3 production completely originates from N2 reduction. Meanwhile, theoretical calculations and X-ray fine structure analysis reveal that the Fe–N3 coordination of Fe SAC/N–C is indeed responsible for the suppression of HER, particularly resulting in a maximum activation of NRR intermediates to produce ammonia with a high yield rate.
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