Preparation Of Self-supporting Non-precious Metal Hydroxide And Its Electrocatalytic Perfor Mance

Hydrogen production by electrochemical water splitting is recognized as an important method of hydrogen production in the future because it has the advantages of readily available raw materials,abundant reserves,and high product purity.Transition metal hydroxides are considered as highly efficient dual-functional electrocatalysts because of the excellent electrocatalytic activity in hydrogen evolution reaction?HER?and oxygen evolution reaction?OER?.In this paper,self-supporting ternary metal hydroxide catalyst materials was prepared.It was found that the morphology and electrical performance of non-precious metal hydroxide catalysts were depended on component.Thus,an optimized catalytic activity was obtained by adjusting the component.The main contents of this paper are as follows:the ternary metal hydroxide CoNiFe-311/NF was synthesized by electrodeposition in a one-step method,and the Fe-311/NF with hierarchical structure on the nickel foam?NF?and titanium sheet?Ti?were prepared by electrodeposition in a stepwise method.Hydroxide layered double hydroxides and layered triple hydroxides on nickel foam were prepared by electrodeposition.After the introduction of Fe and Ni into the cobalt hydroxide,the morphology of the sample changed from regular hexagons to floccular spherical structures,which resulted in phase interfaces.At the same time,the crystal lattice tended to be disordered,exposing more active site.In LSV testing,CoNiFe-311/NF showed the best electrochemical activity.As a dual-functional water splitting catalyst,at a current density of 50 mA cm^-2,the over potential of OER and HER are 90 and 162 mV,and the over potential of over water splitting is 1.59 V.It still maintains good electrochemical activity after a constant current discharge for 12 h.Fe-311/NF and Fe-311/Ti were prepared by stepwise deposition.In this paper,a catalyst with a hierarchical structure was deposited on titanium sheets and nickel foam.Microcracks appeared on the first layer of sediments.Microcracks can enhance the combination of the two layers without obvious influence on the second layer.And at the same time microcracks provide more channels for the transportation of ions,and so enhance the catalytic activity.In the investigation of the influence of the substrate on the reaction activity of the product,it was found that nickel foam will participate in the reaction at a high potential,which affects the determination of the catalytic activity of the product.