Composition-Dependent Catalytic Activities of Noble-Metal-Free NiS/Ni3S4 for Hydrogen Evolution Reaction

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• 作者：Zhixiao Qin ; Yubin Chen ; Zhenxiong Huang ; Jinzhan Su ; Zhidan Diao ; Liejin Guo
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：July 14, 2016
• 年：2016
• 卷：120
• 期：27
• 页码：14581-14589
• 全文大小：565K
• 年卷期：0
• ISSN：1932-7455

文摘

The development of efficient noble-metal-free hydrogen evolution catalysts is quite appealing with the aim of providing cost-competitive hydrogen. Herein, nickel sulfides (NiS_x) with tunable NiS/Ni₃S₄ molar ratios were synthesized via a simple hydrothermal method. Detailed electrochemical studies under neutral conditions indicated that the electrocatalytic property of NiS_x catalysts was determined by the composition. Notably, the NiS_x sample with the NiS/Ni₃S₄ molar ratio of 1.0 exhibited the lowest overpotential and charge-transfer resistance. As analyzed from the Tafel plots, the rate-determining step of NiS_x catalysts for hydrogen generation was the Volmer step, in which the proton adsorption played a key role. Theoretical calculation revealed that NiS and Ni₃S₄ exhibited the metallic behaviors with different work functions. Consequently, the NiS_x sample with the NiS/Ni₃S₄ molar ratio of 1.0 owned the most adsorbed protons, which led to the highest electrocatalytic property. Meanwhile, NiS_x was demonstrated to be efficient cocatalysts to promote photocatalytic hydrogen generation. NiS_x/CdS with the NiS/Ni₃S₄ molar ratio of 1.0 showed the best photocatalytic activity with the apparent quantum efficiency of 56.5% at 420 nm. This result was in good agreement with the electrocatalytic activities of NiS_x samples, indicating the intrinsic property for efficient hydrogen generation.