CSIR-Central Electrochemical Research Institute , Karaikudi 630003 , Tamilnadu , India.
Academy for Scientific and Innovative Research , New Delhi , India.
Langmuir. 2018 May 15;34(19):5374-5380. doi: 10.1021/acs.langmuir.7b03321. Epub 2018 Apr 30.
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.
在这项工作中，我们报告了电化学合成的 WS 量子点（QD）（约 3nm）在多晶金电极上的吸附动力学。我们采用 Langmuir 吸附等温线方法研究了实验计算得到的吸附平衡常数（K）和吸附自由能（ΔG）随温度和吸附物浓度的变化关系。随后，我们提取了其他热力学参数，如吸附速率常数（K）、解吸速率常数（K）、吸附焓（ΔH）和吸附熵（ΔS）。研究结果表明，ΔG 随温度变化，约为-7.64±0.6kJ/mol；ΔH=-43.72±1.7kJ/mol；ΔS=-0.126±0.017kJ/（mol·K）。这些对焓和熵力对体系总自由能贡献的研究强调了熵力对 WS QD 单层稳定性的作用，并为其他过渡金属二卤代物量子点（TMDQD）单层提供了新的热力学见解。
