Research On Hydrogen Production System Based On Copper And Nickel Non-precious Metals

At present,the world is confronted with two major problems,namely energy and environment problem.On the one hand,the demand for energy is gradually increasing,conversely,fossil energy reserves are declining.At the same time,the extensive use of traditional fossil fuel(coal,oil and gas)has given rise to numerous environmental problems,such as air pollution and the greenhouse effect,the latter causing potentially catastrophic climate changes.To replace fossil fuels,it is particularly urgent to use renewable energy in a sustainable way.Nowadays,various types of sustainable eco-friendly energy is emerging,which includs solar energy,wind energy,tidal energy,nuclear energy,biomass energy,hydrogen,etc.Among of them,hydrogen energy is considered as the ideal energy in the 21st century owning to its high specific enthalpy of combusion and benign combustion product(water).In addition,water is regarded as one of the most abundant resources in the world and it can be used to produce hydrogen by water splitting.Thus the development and utilization of hydrogen energy shows a promising prospect.Water splitting reaction is not a natural process from thermodynamics,so external energy input is necessary.Among of them,electrocatalytic water splitting,photocatalytic water splitting and photoelectrochemical water splitting are commonly researched.At the same time,water splitting reactions including water oxidation(O2)and water reduction(H2)are both involved with multi-electron transfer processes,which will inevitably cause reaction kinetic energy barrier.So extra potential namely overpotential has to be applied.In order to lower overpotential,the development and preparation of economical,earth-abundant,stable and efficient catalysts play important role.For water reduction reaction,noble metal Pt currently is the most efficient catalyst,but expensive cost and rare reserve limits its large-scale application,therefore people gradually pay attention to cheap transition metal catalysts including iron,cobalt,nickel,copper,etc.With its earth-abundance,non-toxicity and biocompatibility,copper and nickel catalysts are attracting people's attention.In this paper,research works mainly focus on the following contents:1.Electrocatalytic hydrogen evolution of the Cu-based film prepared in neutral aqueous solution by electrodepositionIn this paper,we synthesized a water-soluble divalent copper complex and performed a comparable hydrogen evolution activity.Further,we prepared an ultra-thin Cu-based film in neutral mild condition by electrodeposition,which had small copper loading on the GC electrode and showed an excellent TOF value reaching 734 h-1 in pH 7 phosphate buffer with continuous 8 h control potential electrolysis.XPS(X-ray Photoelectron Spectroscopy)analysis exhibited there was no noble metal Pt in the film.Meanwhile,in-depth analysis for C 1s and N 1s found that ligand may be contained in the active Cu-based film and have the inhibited effect for the release of copper ion,which will make the Cu-based film keep stable in the process of hydrogen evolution.2.Binary nickel-based materials used for photocatalytic hydrogen evolution in waterThe research work firstly synthesized a kind of soluble nickel-based complex and then verified the interation force between NiL complexes and quantum dots by ultraviolet visible spectra,steady state fluorescence spectra.Under the optimization of system,the binary nickel-based material was prepared through the potential interation force.Through addition of the ascorbic acid and 220 min continuous light,the binary nickel-based material dispersed into the water at pH 7 showed a comparable hydrogen evolution amount with the value of 16.4 mL.Finally,the photocatalytic mechanism of the binary nickel-based material initially worked out the process of electron transfer from the hybrid catalysts.