Solar Energy Laboratory, Department of Chemistry, Thiruvalluvar University, Vellore 632 115, Tamilnadu, India
Centre of Excellence for Energy Research, Sathyabama Institute of Science and Technology, Chennai 600 119, India
基于塔菲尔方程式的电化学分析被广泛用于析氢反应（HER）中，以评估和表征电催化剂。Tafel斜率和交流电流密度是不变地获得并针对文献中的Tafel方程进行讨论的仅有的两个参数。在此，讨论了在HER分析中对Tafel常数的见解，并指出了其实际优势。建议将Tafel常数视为HER的发病潜能。当其他参数（如塔菲尔斜率或交换电流密度）相同时，塔菲尔常数成为两种电催化剂之间的定义参数。使用CoSe
2
和NiSe
2
说明了相同的Tafel常数的重要性
。研究了一系列Co
（1–
x
）
Ni
x
Se
2中
Tafel常数的变化。两种电催化剂之间出现相同的Tafel常数会导致一种电催化剂在较低电流状态下成为更好的催化剂，而另一种在较高电流状态下表现出更高的活性。此外，这里提出的概念被应用于几个文献实例，并确定了Tafel常数在HER分析中的意义。
Tafel-equation-based electrochemical analysis is widely employed in hydrogen evolution reaction (HER) to evaluate and characterize electrocatalysts. Tafel slope and exchange current density are the only two parameters that are invariably obtained and discussed with respect to Tafel equation in the literature. Herein, insights on Tafel constant in the analysis of HER are discussed, and its practical advantage is indicated. It is proposed that Tafel constant can be considered as the onset potential of HER. Tafel constant becomes the defining parameter between two electrocatalysts when other parameters such as Tafel slope or exchange current density become same. The significance of the same Tafel constants is illustrated using CoSe
2
and NiSe
2
. Variation of the Tafel constant within a series of Co
(1–
x
)
Ni
x
Se
2
is examined. The occurrence of the same Tafel constants between two electrocatalysts leads to one electrocatalyst becoming the better catalyst in the lower current regime, whereas the other exhibits higher activity in the higher current regime. Furthermore, concepts developed here are applied to several literature examples, and the significance of Tafel constant in the analysis of HER is established.
