Studies On The Syntheses And Electrochemical Performances Of Metal Sulfides Nanostructures

The rapid consumption of fossil fuels and increasingly serious environmentalproblems make the development of sustainable energy technology an urgent task.Hydrogen?H₂?has a high-quality specific energy density,and is proposed to be a major energy resource in the future world.At present,H₂ production still relies mainly on the fossil fuel industry,with low purity and high cost.One of the most effective ways to produce H₂ at low cost and high purity is to split water into hydrogen and oxygen by electricity or solar energy.Some precious metals and their oxides are currently recognized as the most advanced electrolyzed water catalysts because they have the lowest overpotential at the same current density and are well stabilized.However,due to the scarcity of resources and high cost of these catalysts,their commercial applications are greatly limited and cannot be widely used in the electrolysis water industry to obtain economical H₂ energy.Therefore,in order to replace these expensive catalysts,the design,synthesis and characterization of transition metal element-based electrocatalysts,which are low in cost,high in activity,and have good stability under long-term catalytic conditions,have been widely practiced.This makes the overall water decomposition more practical.The specific research contents and innovative achievements of this paper are as follows:?1?Co,Fe co-doped MoS₂?Co,Fe-MoS₂?nanosheets assembled architecture is successfully prepared using prussian blue analogue of Co₃[Fe?CN?₆]₂ nanocubes as a self-sacrifice template.Nanosheets assembled architecture supplies structural benefits of high surface area,easily accessible active sites,and short charge transfer path.The defects generated from the Co,Fe doping provide additional catalytic sites.When used as bifunctional catalysts for water electrolysis,the Co,Fe-MoS₂ shows excellent catalytic activity with a low cell voltage of 1.47 V at a current density of 10 mA cm^-2.In a two-electrode electrolyzer,only one single-cell AA battery?nominal voltage of 1.5V?could afford the sustainable overall water splitting.?2?Novel CoFeP nanocages are obtained from CoFe-PBA nnaocubes precursor via a facile phosphidation route.The porous hollow structure and unique multivoid interior provide exposed active sites and high surface area.For the CoFeP catalyst,both Co and Fe serve as active sites,and the synergism between them induces optimized electric structure.The resulting CoFeP nanocages are employed as advanced OER catalyst in alkaline medium,which deliver a current density of 10 mA cm^-2 at a very low overpotential of 180 mV,a small turnover frequency of 0.93 s^-1 at overpotential of 270 mV,and superior stability.?3?The cubic NiCo-PBA bricks assembled 2D nanowalls on Ni foam are constructed through a Ni?OH?₂ nanosheet confined template technique.A great number of sites are generated along the borders of brick subunits,and the 2D feature supplies downscaled charge diffusion path and high accessible surface area.Therefore,NiCo-PBA/NF exhibits impressive water electrolysis activities,with low overpotentials of 140 and 62 mV at 10 mA cm^-2 for OER and HER,respectively.Moreover,the NiCo-PBA/NF coupled two-electrode system achieves a low cell potential of 1.49 V at 10 mA cm^-2 for overall water splitting,which is even better than the noble metal based IrO₂-Pt/C system.