Design And Synthesis Of Novel Nickel Sulfides And Their Electrocatalytic Performance For Water Splitting

In the past decade,tens of thousands of fossil fuels resource was exploited and utilized which lead to the increasing environmental problem,greenhouse effect,water pollution and etc.Many coping strategies were put forward and renewable hydrogen was one of promising strategy.To achieve sustainable hydrogen production,water splitting is favorable strategy benefiting from abundant water resources.However,its practical applied was impeded by sluggish reaction in anode and cathode.The noble-metal?Pt-based and Ru-based?catalysts are considered as most efficient electrocatalysts for water splitting.However,the scarcity and high price of precious metals have been impeded their development.Thus,developing high active electrocatalyst for water splitting is an urgent task.Many materials have aroused great attention in this field.The family of nickel-based sulfide is one of examples that possess interesting property in water splitting fields.In this paper,our researches focus on several kinds of nickel sulfides.Specifically,we synthesize several novel materials and propose design concepts of advanced material.A miraculous construction of tree-like array?NiS-Ni₃S₂/NF heterostructure?,which directly grew on nickel foam substrate,was synthesized via one-step hydrothermal process.This novel tree-Like NiS-Ni₃S₂/NF heterostructure array shows a tremendous potential for the oxygen evolution reaction?OER?as a catalyst in practice.More specifically,tree-Like NiS-Ni₃S₂/NF heterostructure array exhibits notable activity and stability toward OER.Tree-Like NiS-Ni₃S₂/NF heterostructure array have a high specific surface area which could provide more active site.Moreover,tree-Like NiS-Ni₃S₂/NF heterostructure array has synergistic effect that could improve the OER performance.The high activity of tree-Like NiS-Ni₃S₂/NF heterostructure array also may stem from the tight conjunction between trees-like NiS/Ni₃S₂ heterostructure array and Ni foam substrate which is beneficial to electronic transmission.And the hydroxy can dramatically gather in the surface of tree-like array,and it would generate some nickel-based oxide which is favorable to OER.It is no doubt that the unique tree-Like NiS-Ni₃S₂/NF heterostructure array has a great promising as alternatives electrocatalyst for OER.What is more,a controllable and simple strategy to synthesize nickel sulfides?NiS₂hollow microspheres and NiS porous hollow microspheres?was proposed.Firstly,we fabricated NiS₂ hollow microspheres via a hydrothermal process.After a precise heat control in specific atmosphere,NiS porous hollow microspheres were prepared.Two novel nickel sulfides?NiS₂ hollow microspheres and NiS porous hollow microspheres?are prepared through this synthesis route.According to the literatures,NiS₂ catalyst was usually applied in hydrogen evolution reaction?HER?,while NiS catalyst was used in oxygen evolution reaction?OER?.Indeed,when we applied them in practical electrocatalysis,they show a marvelous electrochemical performance.The structure of the hollow microspheres is favor of ease the volume change during the electrocatalytic reaction,and the porous structure is benefit for the infiltration of the electrolyte and the release of bubbles.Therefore,when the nickel sulfides are used as catalysts for the electrolysis of water,they exhibite excellent electrocatalytic properties.It is enlighten us to make an efficient water splitting system,including NiS₂ as HER catalyst in cathode and NiS as OER catalyst in anode.The system shows high-activity and good stability,which has a great potential in others field.