Liu Wengang, Chen Yinjuan, Qi Haifeng, Zhang Leilei, Yan Wensheng, Liu Xiaoyan, Yang Xiaofeng, Miao Shu, Wang Wentao, Liu Chenguang, Wang Aiqin, Li Jun, Zhang Tao
State Key Laboratory of Catalysis, and Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 ZhongShan Road, Dalian, 116023, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Angew Chem Int Ed Engl. 2018 Jun 11;57(24):7071-7075. doi: 10.1002/anie.201802231. Epub 2018 May 9.
Hydrothermally stable, acid-resistant nickel catalysts are highly desired in hydrogenation reactions, but such a catalyst remains absent owing to the inherent vulnerability of nickel under acidic conditions. An ultra-durable Ni-N-C single-atom catalyst (SAC) has now been developed that possesses a remarkable Ni content (7.5 wt %) required for practical usage. This SAC shows not only high activities for hydrogenation of various unsaturated substrates but also unprecedented durability for the one-pot conversion of cellulose under very harsh conditions (245 °C, 60 bar H , presence of tungstic acid in hot water). Using integrated spectroscopy characterization and computational modeling, the active site structure is identified as (Ni-N4)⋅⋅⋅N, where significantly distorted octahedral coordination and pyridinic N constitute a frustrated Lewis pair for the heterolytic dissociation of dihydrogen, and the robust covalent chemical bonding between Ni and N atoms accounts for its ultrastability.
水热稳定、耐酸的镍催化剂在加氢反应中具有很高的需求，但由于镍在酸性条件下固有的脆弱性，这种催化剂仍然不存在。现在已经开发出一种超耐用的Ni-N-C单原子催化剂（SAC），它具有实际应用所需的显著镍含量（7.5 wt %）。这种SAC不仅对各种不饱和底物的加氢反应具有高活性，而且在非常苛刻的条件下（245 °C，60 bar H ，热水中存在钨酸）对纤维素的一锅法转化具有前所未有的耐久性。通过综合光谱表征和计算建模，活性位点结构被确定为(Ni-N4)⋅⋅⋅N，其中严重扭曲的八面体配位和吡啶型N构成了用于氢气异裂解离的受阻路易斯对，并且Ni和N原子之间强大的共价化学键解释了其超稳定性。
