MoS_(2)/Ru异质结构的制备及其电催化析氢反应性能

Synthesis and electrochemical hydrogen evolution reaction properties of MoS_(2)/Ru heterostructures

二维层状二硫化钼(MoS_(2))是一种非常有前景的替代贵金属铂的电水解制氢催化剂。然而,MoS_(2)电子导电性较差,且在碱性氢析出反应(HER)中对水分子吸附/裂解的活化能垒较高,限制其在碱性电水解的应用。通过一步水热法将MoS_(2)纳米片均匀生长在三维导电碳布(CC)上,以有效提高电极导电性。随后在RuCl_(3)的乙醇溶液中通过溶剂热法可控制备超小Ru纳米颗粒负载MoS_(2)纳米片,形成CC@MoS_(2)/Ru异质结构。Ru的负载能有效促进水吸附/裂解反应,从而和MoS_(2)协同催化HER。采用X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等方法对MoS_(2)/Ru进行结构和形貌表征。结果表明:MoS_(2)呈纳米片状交错生长在碳布上,并且超小Ru纳米颗粒(平均粒径2.5 nm)均匀负载在MoS_(2)纳米片上。将CC@MoS_(2)/Ru作为工作电极,石墨棒和Hg/HgO电极分别为对电极和参比电极进行碱性HER测试。在电流密度为-10 mA·cm^(-2)下的过电位仅为71.3 mV,Tafel斜率为104.8 mV·dec^(-1)。通过对其进行计时电位滴定法稳定性测试,发现在恒电流密度-10 mA·cm^(-2)下能够维持至少35 h而没有明显性能衰减。

Two-dimensional layered MoS_(2) is considered to be a promising electrocatalyst alternative to Pt for water splitting.However,low electronic conductivity and high energy barrier of water adsorption/dissociation of MoS_(2) during alkaline hydrogen evolution reaction(HER)limit its application in water splitting.In this work,the smoothly anchored of MoS_(2) nanosheet on carbon cloth(CC)was prepared by one-pot hydrothermal method.The CC can significantly improve the electronic conductivity.Subsequently,the MoS_(2) nanosheet supported ultra-small Ru nanoparticles were controllably prepared by solvothermal reaction through immersing CC@MoS_(2) in an ethanol solution containing RuCl_(3) and finally formed CC@MoS_(2)/Ru heterostructure.Ru can promote water adsorption/dissociation,and then synergistically catalyze HER with MoS_(2).The CC@MoS_(2)/Ru is characterized by X-ray powder diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscope(SEM),and transmission electron microscope(TEM),etc.The results show that the MoS_(2) nanosheets crossedly aligned on the CC,and the ultra-small Ru nanoparticles(average grain diameter of 2.5 nm)are dispersed homogeneously on the MoS_(2) nanosheets.The CC@MoS_(2)/Ru is working electrode,the graphite rod and Hg/HgO are counter and reference electrodes,respectively.The alkaline HER are tested and the overpotential is only 71.3 mV to achieve the current density of-10 mA·cm^(-2),the Tafel slope of CC@MoS_(2)/Ru is 104.8 mV·dec^(-1).The chronopotentiometry is performed at-10 mA·cm^(-2) to evaluate the stability of CC@MoS_(2)/Ru.After the 35 h,the neglectable potential attenuation can be observed.