Study And Preparation Of Nickel Involved Electrocatalysts On Deeply Polished Titanium For Water Splittig

Growth of population and development of technology in modern and rapid development society,and the people’s standard of living have taken place great changes.In order to support people’s daily life needs,the demand for energy is also more and more.Environmental pollution and the limitations of fossil energy forced human to explore new continuous energy.Hydrogen is an environmental friendly and high efficiency,therefore,hydrogen is considered as the one of the most potential energy for our future.In the current technology of hydrogen production,electrolysis of water is the most environmental and sustainable.But the technology is one of the biggest challenges is to reduce energy consumption of the electrolysis and must find a suitable catalyst for hydrogen evolution to reduce hydrogen overvoltage.Platinum group metals have been confirmed by a large number of studies are the electronic transmission is the fastest and high efficiency catalyst for hydrogen evolution reaction.However,the large scale applications of platinum carbon catalysts are limited due to the rare content in earth and the expensive price.Transition metal sulfides and phosphide compounds are a type of new-emerging,promising electrocatalyst for HER,MoS2 and Mo3P are representative of them.Transition metal sulfides and phosphide compounds prepared by the author were characterized by way of X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and other means in this paper.The main contents are as follow:1.Precursor composite NiMoO4 nanowires and Ni(OH)2 nanosheets was grown on Ti substrate by simple hydrothermal method.Before the growth of composite,the Ti sheet was sequentially cleaned by sonication in mixed solution(acetone and 10 wt%sodium hydroxide v:v = 1:1)for 30 min.After cleaning,Ti sheet was immersed in sulfuric acid at 95℃ for 2 h.Based on the results of electrochemical performance test,the precursors were improved.2.The prepared precursors grown on Ti substrate and 1g sublimed sulfur(S)were put at two separate positions in a porcelain boat with S at the upstream side of the furnace,and then,the samples were sulfurized at 500℃ for 1 h.The results of electrochemical show that in the 1 M KOH electrolyte,the overpotential of hydrogen evolution reaction of 91 mV,current density can be up to 10 mA/cm2,and the Tafel slope value is 54.5 mV/dec.At the same time,the catalyst performing a good stability in alkaline electrolyte.3.Also using the method of chemical vapor deposition,using red phosphorus as the source of phosphorus,Ni(OH)2@Ti nanosheets and NiMoO4@Ti nanowires precursor by phosphating.Ni(OH)2@Ti obtained pure phase NiP2 after phosphating,onset overpotential is 71.5 mV in the 1 M KOH electrolyte,tafel slope is 61 mV/dec,and overpotential of 250 mV current density can reach 100 mA/cm2.In the 0.5 M H2SO4 electrolyte,onset overpotential is 89 mV,tafel slope is 50.2 mV/dec,and overpotential of 194 mV current density can reach 100 mA/cm2.Furthemore,good stability in alkaline and acid electrolyte.The characterization analysis result is Mo3P-MoO3 after phosphating NiMoO4@Ti.According to the electrochemical data of Mo3P-MoO3 hydrogen evolution,in the 1 M KOH electrolyte effect is best,tafel slope value is 85.1 mV/dec,and current density of 100 mA/cm2 needed for the overpotential of 297 mV.The polarization curve before and after 1000 cycles is shifted around 50 mV when the current density is 100 mA/cm2.