Wu Tong, Song Erhong, Zhang Shaoning, Luo Mengjia, Zhao Chendong, Zhao Wei, Liu Jianjun, Huang Fuqiang
State Key Lab of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
Adv Mater. 2022 Mar;34(9):e2108505. doi: 10.1002/adma.202108505. Epub 2022 Jan 20.
Alkaline water electrolysis is commercially desirable to realize large-scale hydrogen production. Although nonprecious catalysts exhibit high electrocatalytic activity at low current density (10-50 mA cm ), it is still challenging to achieve industrially required current density over 500 mA cm due to inefficient electron transport and competitive adsorption between hydroxyl and water. Herein, the authors design a novel metallic heterostructure based on nickel nitride and monoclinic molybdenum disulfide (Ni N@2M-MoS ) for extraordinary water electrolysis. The Ni N@2M-MoS composite with heterointerface provides two kinds of separated reaction sites to overcome the steric hindrance of competitive hydroxyl/water adsorption. The kinetically decoupled hydroxyl/water adsorption/dissociation and metallic conductivity of Ni N@2M-MoS enable hydrogen production from Ni N and oxygen evolution from the heterointerface at large current density. The metallic heterostructure is proved to be imperative for the stabilization and activation of Ni N@2M-MoS , which can efficiently regulate the active electronic states of Ni/N atoms around the Fermi-level through the charge transfer between the active atoms of Ni N and MoMo bonds of 2M-MoS to boost overall water splitting. The Ni N@2M-MoS incorporated water electrolyzer requires ultralow cell voltage of 1.644 V@1000 mA cm with ≈100% retention over 300 h, far exceeding the commercial Pt/C║RuO (2.41 V@1000 mA cm , 100 h, 58.2%).
碱性水电解对于实现大规模制氢在商业上具有吸引力。尽管非贵金属催化剂在低电流密度（10 - 50 mA cm²）下表现出高电催化活性，但由于电子传输效率低下以及羟基与水之间的竞争性吸附，要实现超过500 mA cm²的工业所需电流密度仍然具有挑战性。在此，作者设计了一种基于氮化镍和单斜相二硫化钼（Ni₃N@2M-MoS₂）的新型金属异质结构用于卓越的水电解。具有异质界面的Ni₃N@2M-MoS₂复合材料提供了两种分离的反应位点，以克服竞争性羟基/水吸附的空间位阻。Ni₃N@2M-MoS₂的动力学解耦的羟基/水吸附/解离和金属导电性使得在大电流密度下能够从Ni₃N产生氢气并从异质界面析氧。事实证明，金属异质结构对于Ni₃N@2M-MoS₂的稳定和活化至关重要，它可以通过Ni₃N的活性原子与2M-MoS₂的Mo-Mo键之间的电荷转移有效地调节费米能级周围Ni/N原子的活性电子态，以促进整体水分解。集成了Ni₃N@2M-MoS₂的水电解槽在1000 mA cm²时需要超低的电池电压1.644 V，在300小时内保持率约为100%，远远超过商业Pt/C║RuO₂（在1000 mA cm²时为2.41 V，100小时，58.2%）。
