Investigation of hydrogen evolution kinetics of metal-doped MoS2 electrocatalysts by exploring the charge transfer coefficients

IF 4.1 3区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Electroanalytical Chemistry Pub Date : 2025-03-29 DOI:10.1016/j.jelechem.2025.119095

Nayana K , Sunitha A.P.

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Abstract

Charge transfer coefficient (α) is an intrinsic activity parameter of hydrogen evolution reaction (HER), as it deals with the fraction of supplied energy used to increase the HER kinetics. This article investigated the HER kinetics of MoS₂, aluminium (Al-MoS₂) and tin (Sn-MoS₂) doped MoS₂ nanostructures by estimating the exact values of α. This article proposes a simple method of the least square curve fitting of the Butler-Volmer equation on the experimentally produced polarization curve of HER to derive α. Since the charge transfer coefficient depends on the current density, in curve fitting, values of α are determined at three different current density regions. The correctness of the estimated α was verified by comparing it with the same derived from Tafel plots of experimental values. Overpotential, Tafel slope, Turnover frequency (TOF), double layer capacitance, electrochemically active surface area (ECSA) and exchange current densities were estimated to confirm the reliability of obtained α values. All electrocatalytic parameters show that Al-MoS₂ has excellent HER activity with overpotential: 249 mV at 10 mA/cm², Tafel slope: 67 mV/Dc, TOF: 0.32 s⁻¹, double layer capacitance: 17 mF/cm², ECSA: 425/cm² and Exchange current density: 1.38 mA/cm². The estimated value of α for Al-MoS₂ is 0.89 at the current density region −5 mA/cm² and − 15 mA/cm² which exhibit the excellent electrocatalytic activity of the catalyst. Estimation of the exact value of α will help to understand the exact electrocatalytic mechanism of the catalyst.

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来源期刊

Journal of Electroanalytical Chemistry 化学-电化学

CiteScore

7.80

自引率

6.70%

发文量

912

审稿时长

2.4 months

期刊介绍： The Journal of Electroanalytical Chemistry is the foremost international journal devoted to the interdisciplinary subject of electrochemistry in all its aspects, theoretical as well as applied. Electrochemistry is a wide ranging area that is in a state of continuous evolution. Rather than compiling a long list of topics covered by the Journal, the editors would like to draw particular attention to the key issues of novelty, topicality and quality. Papers should present new and interesting electrochemical science in a way that is accessible to the reader. The presentation and discussion should be at a level that is consistent with the international status of the Journal. Reports describing the application of well-established techniques to problems that are essentially technical will not be accepted. Similarly, papers that report observations but fail to provide adequate interpretation will be rejected by the Editors. Papers dealing with technical electrochemistry should be submitted to other specialist journals unless the authors can show that their work provides substantially new insights into electrochemical processes.