Advanced science: in situ electrochemical synthesis of core shell NiFe Sn @ NiFe (OH) oxides and their catalytic oxygen evolution
traditional fossil energy (such as coal oil natural gas) promotes the rapid development of human society but also brings some challenges such as energy crisis environmental pollution greenhouse effect so on. As a potential energy carrier in the future hydrogen can be obtained by electrolysis of water. Considering that the oxygen evolution reaction involves multiple electrons protons it is the bottleneck step of water electrolysis. Therefore it is of great significance to develop appropriate strategies for the preparation of efficient oxygen evolution catalysts.
Luo Jingli academician of School of materials of Shenzhen University Fu Xianzhu Professor have synthesized the materials with core-shell structure by an in-situ electrochemical strategy. Firstly nifesn alloy nanospheres were prepared by electrochemical deposition method then the surface of nifesn alloy nanospheres was oxidized to NiFe (oxy) hydroxide by anodization under alkaline conditions NiFeSn@NiFe (oxy)hydroxide。 The Sn on the surface of nifesn alloy nanospheres can be dissolved by forming a complex with hydroxyl at a positive potential resulting in the formation of oxygen vacancy defects can provide a larger specific surface area of electrochemical activity. In addition the ratio of nickel to iron in the catalyst prepared by this strategy is also easy to control. Among them the overpotential required for the optimized catalyst to reach the current density of 10 Ma cm − 2 in 1 m KOH is only 260 MV which can be maintained for 40000 s without attenuation at 10 Ma cm − 2 shows high TOF value mass activity.
combined with a series of characterization means the excellent catalytic activity of nifesn is due to its unique structure: the core of nifesn has good conductivity which can ensure the effective electron transfer for the shell of NiFe (oxy) hydroxide In turn the shell of (oxy) hydroxides insulates the core of nifesn from contact with the electrolyte which can prevent it from being oxidized. Moreover there are oxygen vacancies large electrochemically active surface area in the shell of NiFe (oxy) hydroxides which are conducive to further catalytic oxygen evolution reaction. The researchers of
believe that this research will provide a new idea for the design of efficient electrochemical catalysts take a solid step towards large-scale application.
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