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Intrinsic Electrocatalytic Activity of Single MoS2 Quantum Dot Collision on Ag Ultramicroelectrodes
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2021-02-08 , DOI: 10.1021/acs.jpcc.0c09644 Hao Wang 1 , Haoran Tang 1 , Yongxin Li 1
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2021-02-08 , DOI: 10.1021/acs.jpcc.0c09644 Hao Wang 1 , Haoran Tang 1 , Yongxin Li 1
Affiliation
It is still a challenge to identify the intrinsic electrocatalytic activity of single MoS2 quantum dots (QDs) because their characterization usually dissects contributions from a large amount of particles. Herein, we demonstrate a single-entity electrochemical method to help us investigate the enhancing hydrogen evolution reaction (HER) activity at the single MoS2 QD level by using silver ultramicroelectrodes (UMEs). At Ag UMEs, the i–t response for MoS2 QD collision consists of repeated current “spikes” that return to the background level as hydrogen formation and covering the QD surface. In contrast, a stepwise “staircase” i–t response is observed for MoS2 QDs colliding on carbon UMEs (C UMEs). The results also show that the current density of single MoS2 QD collision on Ag UMEs is much higher than on C UMEs, revealing the impact of the unique property of the metal–MoS2 interface on HER performance, which has been demonstrated by thermodynamic analysis and density functional theory (DFT) calculations. It has been found that the interactions between MoS2 QDs and substrate UMEs lead to significant changes in the hydrogen adsorption energies (ΔEads) and Gibbs free energy (ΔGH), resulting in the difference in HER activity.
中文翻译:
MoS 2量子点碰撞对Ag超微电极的本征电催化活性
鉴定单个MoS 2量子点(QD)的固有电催化活性仍然是一项挑战,因为它们的特征通常会剖析大量颗粒的贡献。在这里,我们演示了一种单实体电化学方法,以帮助我们通过使用银超微电极(UME)在单个MoS 2 QD水平上研究增强的析氢反应(HER)活性。在Ag UMEs,MoS 2 QD碰撞的i - t响应包括重复的电流“峰值”,这些峰值随着氢的形成并覆盖QD表面而回到本底水平。相反,对于MoS,观察到逐步的“阶梯” i – t响应2个QD碰撞碳UME(C UME)。结果还表明,Ag UMEs上单个MoS 2 QD碰撞的电流密度远高于C UMEs,这表明金属-MoS 2界面的独特性质对HER性能的影响已通过热力学分析得到证明。和密度泛函理论(DFT)计算。已经发现,MoS 2 QD与底物UME之间的相互作用导致氢吸附能(ΔE ads)和吉布斯自由能(ΔG H)发生显着变化,从而导致HER活性的差异。
更新日期:2021-02-18
中文翻译:
MoS 2量子点碰撞对Ag超微电极的本征电催化活性
鉴定单个MoS 2量子点(QD)的固有电催化活性仍然是一项挑战,因为它们的特征通常会剖析大量颗粒的贡献。在这里,我们演示了一种单实体电化学方法,以帮助我们通过使用银超微电极(UME)在单个MoS 2 QD水平上研究增强的析氢反应(HER)活性。在Ag UMEs,MoS 2 QD碰撞的i - t响应包括重复的电流“峰值”,这些峰值随着氢的形成并覆盖QD表面而回到本底水平。相反,对于MoS,观察到逐步的“阶梯” i – t响应2个QD碰撞碳UME(C UME)。结果还表明,Ag UMEs上单个MoS 2 QD碰撞的电流密度远高于C UMEs,这表明金属-MoS 2界面的独特性质对HER性能的影响已通过热力学分析得到证明。和密度泛函理论(DFT)计算。已经发现,MoS 2 QD与底物UME之间的相互作用导致氢吸附能(ΔE ads)和吉布斯自由能(ΔG H)发生显着变化,从而导致HER活性的差异。