Study On The Construction And The Performance Of Molybdenum Disulfide-based Composite Catalyst For Hydrogen Evolution

Molybdenum disulfide（MoS₂）has hydrogen adsorption free energy similar to that of metal platinum,and can obtain exchange current density equivalent to platinum.It can be stably existed in strong acidic solution and rich in resources,and it has become a potential electrocatalytic hydrogen evolution.Replace with a precious metal catalyst.However,at present,the catalytic hydrogen evolution performance of MoS₂ is limited by its less exposed catalytic active sites and poor conductivity.In this thesis,the MoS₂-based catalytic hydrogen evolution electrode is studied.By designing the catalytic hydrogen evolution electrode,the number of catalytic active sites is increased,the carrier injection and migration efficiency are improved,and the catalytic hydrogen evolution performance of the material is greatly improved.The main research contents and results are as follows:（1）Nano-thin layer MoS₂ was prepared by liquid-phase ultrasonic stripping method,and the MoS₂ nano-flakes were respectively fixed on the surface of the polyimide（PI）substrate Teslin paper base containing conductive copper layer by inkjet printing technology,or dispensed.A catalytic electrode is formed on the glassy carbon electrode.The hydrogen evolution performance of these three electrodes shows that the Teslin paper base and copper collector with high roughness are beneficial to the catalytic hydrogen evolution performance.The overpotential of the Teslin paper-based electrode at10 mA cm^-2 is 105 mV,and the Tafel slope is 87 mV dec^-1,the electric double layer capacitor is 5.4 mF cm^-2.（2）Polyvinylpyrrolidone（PVP）was added to the MoS₂ dispersion for liquid phase sonication.The results showed that PVP could act as a surfactant-assisted exfoliation.SEM,TEM and Raman spectroscopy indicated that the size of MoS₂ nanosheets obtained by PVP-assisted stripping was greatly reduced.XPS results showed that PVP-assisted stripping of MoS₂ was changed from semiconductor 2H phase to metal 1T phase.The MoS₂/PVP ink was immobilized on a Teslin paper substrate containing a conductive copper layer by inkjet printing technology to form a catalytic hydrogen evolution electrode.The electrochemical test results showed that the potential of the MoS₂/PVP hydrogen evolution electrode was 66 mV at 10 mA cm^-2.The Tafel slope is 59 mV dec^-1,and the electric double layer capacitance is 10.2 mF cm^-2,which is much higher than that of the MoS₂ hydrogen evolution electrode.（3）PVP and reduced graphene oxide（RGO）were added to the MoS₂ dispersion for liquid phase sonication,and the stripped MoS₂ and RGO were thoroughly mixed,and ink-jet printed on the Teslin paper base containing the conductive copper layer.The MoS₂/PVP/RGO catalytic hydrogen evolution electrode was constructed by changing the inkjet printing pattern configuration and the number of inkjet printing.The electrochemical test results showed that the MoS₂/PVP/RGO constructed under the optimal conditions had an potential of 51 mV at 10 mA cm^-2.The Tafel slope is 32 mV dec^-1 and the electric double layer capacitance is 42.9 mF cm^-2.This indicates that the MoS₂/PVP/RGO electrode has an extremely high catalytic hydrogen evolution activity.