香港城市大学支春义研究团队报道了通过氢键调节质子转移调节固氮中的杠杆关系。相关研究成果于2024年8月19日发表在国际顶尖学术期刊《德国应用化学》。

在电化学氮还原反应（NRR）中，由于竞争性析氢反应（HER），NH₃产生活性和选择性之间存在杠杆关系，这意味着高活性和强质子吸附导致低产物选择性。

该文中，研究人员设计了一种新型的金属有机氢键框架（MOHBF）材料，通过氢键调节的质子转移途径来调节这种杠杆关系。MOHBF材料与还原氧化石墨烯（rGO）复合，形成Ni-N₂O₂分子催化剂（Ni-N₂O₂/rGO）。Ni-O-C和N-O-H中O原子的独特结构可以与H₂O分子形成氢键，干扰质子直接吸附在Ni活性位点上，从而调节质子转移机制并减缓HER动力学，调节杠杆关系。

此外，该催化剂具有丰富的Ni单原子位点，富含Ni-N/O配位，有利于N₂的吸附和活化。Ni-N₂O₂/rGO同时表现出增强的NH₃生产活性和选择性，最大NH₃产率为209.7μg h^-1 mgcat.^-1，法拉第效率为45.7%，优于其他报道的单原子NRR催化剂。

附：英文原文

Title: Modulating the Leverage Relationship in Nitrogen Fixation Through Hydrogen-Bond-Regulated Proton Transfer

Author: Shaoce Zhang, Hu Hong, Rong Zhang, Zhiquan Wei, Yiqiao Wang, Dong Chen, Chuan Li, Pei Li, Huilin Cui, Yue Hou, Shengnan Wang, Johnny C. Ho, Ying Guo, Zhaodong Huang, Chunyi Zhi

Issue&Volume: 2024-08-19

Abstract: In the electrochemical nitrogen reduction reaction (NRR), a leverage relationship exists between NH3-producing activity and selectivity because of the competing hydrogen evolution reaction (HER), which means that high activity with strong protons adsorption causes low product selectivity. Herein, we design a novel metal-organic hydrogen bonding framework (MOHBF) material to modulate this leverage relationship by a hydrogen-bond-regulated proton transfer pathway. The MOHBF material was composited with reduced graphene oxide (rGO) to form a Ni-N2O2 molecular catalyst (Ni-N2O2/rGO). The unique structure of O atoms in Ni-O-C and N-O-H could form hydrogen bonds with H2O molecules to interfere with protons being directly adsorbed onto Ni active sites, thus regulating the proton transfer mechanism and slowing the HER kinetics, thereby modulating the leverage relationship. Moreover, this catalyst has abundant Ni-single-atom sites enriched with Ni-N/O coordination, conducive to the adsorption and activation of N2. The Ni-N2O2/rGO exhibits simultaneously enhanced activity and selectivity of NH3 production with a maximum NH3 yield rate of 209.7 μg h1 mgcat.1 and a Faradaic efficiency of 45.7%, outperforming other reported single-atom NRR catalysts.

DOI: 10.1002/anie.202412830

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202412830