Adsorption Kinetics of WS₂ Quantum Dots onto a Polycrystalline Gold Surface

Abstract

In this work, we report the adsorption kinetics of electrochemically synthesized WS quantum dots (QDs) (ca. 3 nm) onto a polycrystalline gold electrode. The Langmuir adsorption isotherm approach was employed to explore the temperature and adsorbate concentration dependence of the experimentally calculated equilibrium constant of adsorption ( K) and the free energy for adsorption (Δ G). Subsequently, we extract other thermodynamic parameters, such as adsorption rate constant ( K), desorption rate constant ( K), the enthalpy of adsorption (Δ H), and the entropy of adsorption (Δ S). Our findings indicate that Δ G is temperature-dependent and ca. -7.64 ± 0.6 kJ/mol, Δ H = -43.72 ± 1.7 kJ/mol, and Δ S = -0.126 ± 0.017 kJ/(mol K). These investigations on the contribution of the enthalpic and entropic forces to the total free energy of this system underscore the role of entropic forces on the stability of the WS QDs monolayer and provide new thermodynamic insights into other transition-metal dichalcogenide quantum dot (TMDQD) monolayers as well.

Direct Adsorption of Graphene Oxide on a Glassy Carbon Electrode: An Investigation of Its Adsorption and Electrochemical Activity

“…By measuring the OCV, the change in OCV indirectly conveys the adsorption of GO on the GC electrode. In addition, OCV can also be used to determine the coverage (θ) . The coverage refers to the fraction of site adsorbed by GO on the GC electrode.…”

“…In addition, OCV can also be used to determine the coverage (θ). 32 The coverage refers to the fraction of site adsorbed by GO on the GC electrode. Therefore, the normalized OCV values (OCV/OCV max ) give the idea of surface coverage and it is then plotted against time and provided in Figure S8.…”