Preparation And Doping Of Two-dimensional Ultrathin Disulfide For Electrocatalytic Water Splittion

As the environmental pollution and energy shortage have posed a great threat to social development,it is particularly important to look for clean and renewable energy sources.Traditional fossil energy can be replaced by hydrogen for its high energy density and recyclable.Hydrogen can be generated from water by the electrochemical water splitting which need active catalyst materials to increase the efficiency of hydrogen production.So far,platinum is considered to be the most active electrocatalysts in the world,but it is limited by the scarcity and high price of platinum.Molybdenum disulfide is a typical two-dimensional transition metal sulfide material.It is now widely used in electrocatalytic hydrogen production due to the excellent electron-chemical properties and similar hydrogen bonding energy to platinum.However,the catalytic active sites of the pure molybdenum disulfide are limited and the conductivity is poor.In this paper,a simple hydrothermal synthesis was used to synthesis hollow molybdenum disulfide microflakes and the heteroatom-doped molybdenum disulfide materials such as the phosphorus and nickel.In addition,the electrocatalytic properties of these materials have been studied systematically.The catalytic active sites can been increased owing to the large specific surface area of the hollow flake-like structure and the heteroatom doping can increase the defects of materials and enhance the electrical conductivity.1.The hollow molybdenum disulfide microflakes were synthesized by a simple hydrothermal method.The molybdenum source and sulfur source are molybdenum chloride and sodium diethyldithiocarbamate.The growth mechanism of hollow molybdenum disulfide microflakes was explored initially by changing the time and temperature in the hydrothermal reaction process.The unique hollow microflakes have large specific surface area,strong carrying capacity and low density.The electrocatalytic performance can be improved because of the increased active site and the enhanced electron transport in electrocatalytic hydrogen evolution.2.Hollow phosphorus-doped molybdenum disulfide(MoSP)microflakes were prepared by a one-step hydrothermal method.The unique hollow two-dimensional microflakes and the excellent conductivity caused by the synergy of P and S double atoms can increase the active sites and the electronic transmission of hydrogen evolution reaction.Obviously,MoSP show superior electrocatalytic activity than pure Mo S2 with an onset overpotential of 31 mV and a Tafel slope of 45 mV dec-1.Moreover,the MoSP catalyst also exhibits excellent stability.3.The synthesis of double-atom doped hollow molybdenum disulfide(Ni MoSP)microflakes was studied.The doping of Ni and P double atoms can enhance the electrocatalytic performance to a certain degree due to the better conductivity of nickel atoms and the lower electronegativity of P atoms.The hollow Ni MoSP microflakes possess excellent properties,such as the large specific surface area,good electrical conductivity,rich defects,strong carrying capacity,excellent stability and so on.