| Due to the over-reliance of fossil fuels,energy and environmental crisis are becoming increasingly serious.Energy conservation and environmental protection have become the two most pressing challenges on the road to sustainable development of mankind.Hydrogen,which can replace fossil fuels,is considered as the most promising sustainable energy source.Hydrogen production by electrochemical water splitting has attracted extensive attention in this field,as its process is simple,carbon-free and environment-friendly.At present,large-scale production of hydrogen in industry is usually carried out in alkaline environments.Compared with that in acidic solution,hydrogen evolution reaction(Hydrogen evolution reaction,HER)is a relatively sluggish kinetics step in alkaline water splitting.For,alkaline HER,the precious metal platinum(Pt),as the benchmark,is the most active hydrogen evolution catalyst.However,due to the scarcity and high cost of Pt,it is not sustainable for large-scale industrial hydrogen production.Reducing the cost of catalysts while improving their performance has become a challenge in this field.The transition metal Ruthenium(Ru)shows excellent performance in alkaline HER due to its suitable adsorption strength for both H2O and H.In recent years,many strategies have been adopted to prepare efficient ruthenium-based electrocatalysts,including crystal plane control,heteroatom doping,multi-alloy,interface defect engineering,electronic structure control,etc.However,ruthenium-based catalysts still have the following problems:(1)How to improve atomic utilization and reduce the content of precious metal Ru to reduce the cost of catalysts;(2)How to regulate the electronic structure of the active site of Ru based catalyst to make its HER performance close to or comparable to Pt.In order to solve the above problems,the electronic structure of ruthenium-based materials and the adsorption strength of basic HER reactants were regulated and optimized by means of transition metal element doping and heterogeneous interface construction in this paper,which greatly improved the basic HER performance:(1)A small amount of Ru was introduced into the NiV hydroxide and treated by high temperature gas phase in the presence of ammonia.The heterogeneous interface of V and N co-modified Ni/Ru was successfully obtained.In this way,the electronic structure of Ru based catalyst was adjusted,and Ni was used as the active site to promote the water dissociation reaction,which significantly improved the catalytic activity of basic HER.At the current density of 10mA/cm2,only 23mV overpotential was needed,which was lower than the 34mV of commercial Pt/C.(2)NiVRu ternary alloy was successfully prepared by two-step hydrothermal method by introducing trace element of Ru into NiV hydroxide and using high temperature heat treatment.The basic hydrogen evolution properties and principle of NiVRu ternary alloy were studied.Various analytical methods have confirmed that the NiVRu ternary alloy is based on Ni,and the V and Ru are enriched in the Ni surrounding nanoparticles,which has a significant promoting effect on basic HER.Theoretical calculation shows that the binding energy of OH*is greatly enhanced after the adsorption of V atom,which creates a good site for OH adsorption.The adsorption of Ru atom is beneficial to the adsorption of H.The ternary alloy material obtained by this method has very excellent performance,and only needs lOmV overpotential at the current density of 10mA/cm2,which is much lower than the 34mV of commercial Pt/C. |
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