A Study On Hydrogen Production By Water Electrolysis For Hydrogen-powered Vehicles

As a green renewable energy,hydrogen energy is widely regarded as the most promising energy source.Electrochemical water splitting has become a green,energy-saving and efficient way to produce hydrogen.So far,Pt-based materials remain the most effective hydrogen-producing electrocatalyst.However,the high cost,low durability,and low richness hinder their practical applications.Therefore,development of low cost,highly efficient,and durable hydrogen evolution reaction?HER?catalysts to replace noble metal materials is particularly attractive in the field.Among the 2D TMDs family,2D metallic niobium disulfide?NbS₂?and ternary molybdenum sulfoselenide nanosheets(MoSe_x S_2-x)have been received wide attention due to its attractive properties,anisotropic structure,and application prospects in energy and catalysis fields.Herein,we developed a robust synthesis technique consisting of electrochemical exfoliation under alternating currents and subsequent liquid-phase exfoliation to prepare highly-uniform few-layer NbS₂ nanosheets.The obtained few-layer NbS₂material has a 2D nanosheets structure with an ultrathin thickness of³ nm and a lateral size of²?m.Benefiting from the unique 2D structure and highly exposed active sites,the few-layer NbS₂ nanosheets catalyst exhibited an excellent catalytic activity for HER in acid with an overpotential of 90 mV at current density of 10 mA cm^-2,a low Tafel slope of 83 mV dec^-1and a large electrochemically active surface area of 10.9mF cm^-2.Secondly,we developed an ultrathin MoSe_xS_2-x-x nanosheets by using cathodic electrochemical exfoliation approach in non-aqueous electrolytes.The exfoliated MoSe_xS_2-x-x nanosheets demonstrated high structural integrity with lateral dimensions up to¹.5?m and an average thickness of about 3 nm.Owing to the unique ultrathin structure and immensely exposed active sites,the ternary MoSe_xS_2-x-x nanosheets catalyst demonstrated a greatly enhanced electrocatalytic activity for HER in 1.0 M KOH with an overpotential of 123 mV at a current density of 10 mA cm^-2,a low Tafel slope of 123 mV dec^-11 and a large electrochemically active surface area of 2.46 mF cm^-2.In a word,we developed the few-layer NbS₂ nanosheets and ultrathin MoSe_xS_2-x-x nanosheets by using electrochemical exfoliation approach.After characterization and performance testing,the two catalysts all showed excellent catalytic activity for hydrogen evolution,which has certain reference value and practical significance for future research in the field of energy catalysis.