Preparation And Performance Of Nickel-based Chalcogenides Nano Composite Electrode For Water Splitting

The energy crisis and environmental problems caused by the overuse of fossil energy have forced people to have more and more stronger demand for clean energy.Hydrogen energy has the advantages of high energy density and no pollution,which is considered as an ideal clean energy,and hydrogen production by water electrolysis has attracted worldwide attention for its high efficiency and low energy consumption in all hydrogen production technology.However,hydrogen production by water electrolysis still needs to be overly dependent on the noble metal catalyst,which greatly increases its commercial cost,In order to large-scale application of hydrolytic hydrogen production technology,the design and development of a new efficient and cheap hydrogen evolution catalyst has become extremely important.In view of this,the two step method of hydrothermal reaction and chemical vapor deposition was adopted,and the hydrogen electrode with high catalytic activity was prepared by controlling the hydrothermal reaction conditions and chemical vapor phase reaction process.Based on the study of the hydrogen evolution performance,the oxygen evolution behavior was studied and a two-electrode system was constructed for the study of the full water performance.The specific content of the study is as follows:Ni₂（CO₃）（OH）₂ nanowires,by the hydrothermal method,near its own were prepared on the carbon fiber paper after regulating the hydrothermal synthesis conditions.The nanowires were further used as precursors,and the lawn-like NiS₂ nanowires catalyst were prepared by chemical vapor depositon after regulating the hydrothermal synthesis conditions,and it was act as electrode for hydrogen evolution to electrochemical measurements,the result found that NiS₂ nanowires have a lower overpotential（166 mV）driving cathode current density of 10mA·cm^-2 than NiS₂ nanosheets and Ni₂（CO₃）（OH）₂ nanowires and further oxygen evolution reaction test showed that it had a higher oxygen evolution activity and the anode current density of 10 mA·cm^-2 could be driven with an overpotential of only 246 mV.In addition,electrochemical tests were performed using the two-electrode method,and the results showed that it also had good catalytic activity for overall water splitting.The above data shows that it has excellent bifunctional electrocatalytic properties.Hybrid structures of NiSe₂ nanowires and nanoparticles（H-NiSe₂）was grown on CFP by chemical vapor selenization reaction by using Ni₂（CO₃）（OH）₂ NWs as precursor nanowires and NiSe₂ nanoparticles/CFP is prepared by changing the selenization process,and then two kinds of self-supporting electrodes for hydrogen evolution have been obtained.The H-NiSe₂/CFP electrode has higher bifunctional catalytic activity due to its porous structure and fine nanocrystals.H-NiSe₂/CFP required overpotential of 260 mV for HER and 295 mV for OER to deliever current density of 10 mA·cm^-2 in the 1 M KOH solution,which were lower than that of NiSe₂ nanoparticles/CFP（266 mV for HER and 335 mV for OER）,while the former required overpotential of 194 mV than that of the latter（205 mV）to deliever current density of 10 mA·cm^-2 in 0.5 M H₂SO₄ solutions.In addition,its good stability in electrolyte indicates that it has broad application potential in the field of energy conversion technology.