(Ag,Au)/MoS_(2)的电解水性能及等离激元光热作用

(Ag,Au)/MoS_(2) as Electrocatalyst for Water Splitting and Its Thermoplamonics Effect

MoS_(2)是电解水体系的一种备受关注的非贵金属析氢催化剂,优化其活性位点是提高其活性的研究重点.采用水热法在三维导电碳布(CC)上合成了二维片状MoS_(2),将反应温度从200℃调至180℃可保留具有更多活性位点的1T相,相应的MoS_(2)(180)/CC电极表现出相对更低的析氢过电位.利用电化学方法在MoS_(2)(180)/CC上分别沉积Ag和Au纳米粒子,得到Ag/MoS_(2)(180)/CC和Au/MoS_(2)(180)/CC电极.扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)表征结果以及无光照、光照和加热条件下电化学极化曲线、电化学阻抗谱(EIS)和Tafel斜率的测试结果表明,20 nm Ag和30 nm Au的负载及光照条件均可降低析氢过电位和增加电流密度,而体系温升的作用与金属的种类有关.利用COMSOL Multiphysics软件构建MoS_(2),Ag/MoS_(2)和Au/MoS_(2)模型,模拟计算了光照下的电场和温度场,证实了Ag和Au纳米粒子的热等离激元效应及其加速电极反应从而提高电解水析氢性能的作用.

MoS_(2) has expected to become a promising non-precious metal catalyst for hydrogen evolution from water electrolysis,and its performances need to be improved by optimizing its active sites.In this paper,two-dimensional flake MoS_(2) was synthesized on three-dimensional conductive carbon cloth(CC)by hydrothermal method.When adjusting the reaction temperature from 200℃to 180℃,1T phase with more active sites of MoS_(2) can be reserved,and the corresponding MoS_(2)(180)/CC electrode exhibits a relatively lower hydrogen evolution overpotential.Ag/MoS_(2)(180)/CC and Au/MoS_(2)(180)/CC were prepared by deposing Ag and Au nanoparticles on MoS_(2)(180)/CC via electrochemical process,respectively.Based on characterization of scanning electron microscopy(SEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and measurements of polarization curves,electrochemical impedance spectroscopy(EIS)and Tafel slope of the resultant electrodes with and without illustration as well as heating,it can be found that the overpotentials and current densities of Ag/MoS_(2)(180)/CC and Au/MoS_(2)(180)/CC can be improved due to the deposition of 20 nm Ag and 30 nm Au or the condition of irradiation,and the role of temperature rise is related to the type of metal.Furthermore,MoS_(2),Ag/MoS_(2) and Au/MoS_(2) models were constructed by using the COMSOL Multiphysics software,and the electric field and temperature field under illumination were simulated and calculated,confirming thermoplamonics effect of Ag and Au nanoparticles and its role in accelerating the kinetics of the electrode reaction and improving the hydrogen evolution performance of electrolyzed water.