Novel Nickel Based Nano-catalysts For Electro-chemical Reactions

This work mainly focuses on developing nickel based catalysts with high activity and robust durability for anode oxygen evolution reaction（OER）in water electrolysis system,from the views of structure and component.First we fabricated four 2Dα-Ni（OH）₂ samples with different morphologies（denoted as Ni（OH）₂-NB,Ni（OH）₂-NF,Ni（OH）₂-NP and Ni（OH）₂-NS,respectively）and investigated their structure effect on oxygen evolution reaction.It turns out that Ni（OH）₂-NP exhibits the highest performance:260 m V overpotential can deliver 10m A·cm^-2 current density with 10 h stability,because of its faster substance diffusion,favorable kinetics,more exposed active sites and high reactivity of active sites,compared with the other three samples.These advantages of Ni（OH）₂-NP are benefit from its unique and favorable petal-like few-layer structure.The following investigation is about the phosphatized nickel-base catalyst from Ni（OH）₂-NP,mainly on the component effect.We found that Ni_xO/Ni₂P/NF generated in situ from Ni₂P/NF can exhibit even higher oxygen evolution reaction performance:220 m V overpotential can afford 20 m A·cm^-2 current density for 68 h.This remarkable performance comes from the unique sandwich structure:（I）inner NF provides good conductivity and robust structure stability;（II）the middle Ni₂P layer can lower the charge transfer resistance and improve the anticorrosion ability of the core NF;（III）,newly-formed Ni_xO outside has more trivalent Ni species and the loose porous structure,endowing high reactivity and favorable kinetics property to active sites to enhance the activity.By separately investigating structure and component effects of nickel-based catalysts on OER,the present work may give some new insights in catalyst design and pave the way for the large scale application of OER catalysts.