Atomic‐Scale Core/Shell Structure Engineering Induces Precise Tensile Strain to Boost Hydrogen Evolution Catalysis

• DOI: 10.1002/adma.201707301
• Publication Date: 2018-05-08T06:28:24Z
• Authors: Han Zhu; Guohua Gao; Mingliang Du; Jinhui Zhou; Kai Wang; Wenbo Wu; Xu Chen; Yong Li; Piming Ma; Weifu Dong; Fang Duan; Mingqing Chen; Guangming Wu; Jiandong Wu; Haitao Yang; Shaojun Guo
• Keywords: 01 natural sciences; 7. Clean energy; 0104 chemical sciences

AbstractTuning surface strain is a new strategy for boosting catalytic activity to achieve sustainable energy supplies; however, correlating the surface strain with catalytic performance is scarce because such mechanistic studies strongly require the capability of tailoring surface strain on catalysts as precisely as possible. Herein, a conceptual strategy of precisely tuning tensile surface strain on Co9S8/MoS2 core/shell nanocrystals for boosting the hydrogen evolution reaction (HER) activity by controlling the MoS2 shell numbers is demonstrated. It is found that the tensile surface strain of Co9S8/MoS2 core/shell nanocrystals can be precisely tuned from 3.5% to 0% by changing the MoS2 shell layer from 5L to 1L, in which the strained Co9S8/1L MoS2 (3.5%) exhibits the best HER performance with an overpotential of only 97 mV (10 mA cm−2) and a Tafel slope of 71 mV dec−1. The density functional theory calculation reveals that the Co9S8/1L MoS2 core/shell nanostructure yields the lowest hydrogen adsorption energy (∆EH) of −1.03 eV and transition state energy barrier (∆E2H*) of 0.29 eV (MoS2, ∆EH = −0.86 eV and ∆E2H* = 0.49 eV), which are the key in boosting HER activity by stabilizing the HER intermediate, seizing H ions, and releasing H2 gas.