Synthesis,Characterization And Electrocatalytic Oxidation Of Urea/Methanol Of Nickel-based Ultra-thin Two-dimensional Materials

Since the reaction kinetics of the fuel cell is relatively slow,an electrocatalyst is generally added to accelerate the entire reaction.There are many choices of electrocatalysts.Nickel-based two-dimensional materiasl are abundant and have good catalytic properties,so they can be used as an alternative to expensive platinum-based catalysts.However,due to the relatively slow charge transport and reaction kinetics of nickel-based two-dimensional materials,the electrocatalytic efficiency of methanol oxidation?MOR?and urea oxidation?UOR?is still lower than what is expected.It can be seen that increasing the catalytic oxidation of nickel-based two-dimensional materials to fuels such as methanol and urea has become an important issue in this field.Based on this,the dissertation has carried out the following research and innovation.?1?Herein,ultrathin NiO nanosheets with abundant oxygen vacancies is put forward as anapplicable catalytic model to get in-depth insights into the role that oxygen vacancies play in MOR process.Thanks to the ultrathin two-dimensional?2D?features and remarkably modulated electronic structures,ultrathin NiO nanosheets with abundant oxygen vacancies exhibit adramatically improved electrocatalytic activity for MOR,which is significantly higher than that of the sa-mple with less oxygen vacancies and bul k NiO.This work opens a promising and feasible pathway for the design and synthesi s of highly efficientnon-noble MOR catalysts.?2?Microwave-assisted synthesis of Ni?OH?₂ ultrathin nanosheets with porous structure,in-depth understanding of the role of porous structures in the catalytic oxidation of urea.The ultra-thin two-dimensional structure and porous structure expose more Ni atoms on the surface of the catalyst as active sites.In addition,the ultra-thin thickness and porous structure also ensure rapid interfacial charge transfer to increase the rate of reaction of urea catalytic oxidation.Most importantly,the presence of abundant pores in ultra-thin nanosheets not only reduces the energy barrier of urea molecules adsorbing on the catalyst surface,but also accelerates the electron transport along the 2D conductive channel,both of which can optimize the UOR reaction kinetics.?3?The use of a new method to prepare ultra-thin two-dimensional materials provides a new way for the preparation of two-dimensional materials.The ultra-thin and small-sized two-dimensional Ni?OH?₂ nanosheets synthesized in this work are used as electrocatalysts for urea fuel cells,which exhibits superior performance compared to large size Ni?OH?₂.The small size of the ultra-thin two-dimensional Ni?OH?₂ material exposes more edge Ni atoms,and the high activity of the edge Ni can accelerate the entire reaction.