Construction Of Ni And Co-Based Non-Noble Metal Catalysts And Investigation Of Their Electrocatalytic Hydrogen Evolution Performance

With the advancement of industrialization,energy crisis and environmental pollution propel scientists to develop renewable,cleaner and sustainable energy resources to substitute traditional fossil fuels.Hydrogen,on account of its characteristics of numerous sources,high mass energy density and zero carbon emission,has become the favorite in the field of energy research.The traditional production processes of hydrogen（such as coal gasification,methane steam reforming,etc.）are not beneficial for the ecological environment owing to emission of greenhouse gas（carbon dioxide）.In recent years,electrochemical water splitting,as an efficient and clean industrial hydrogen production technology,holds tremendous promise for future energy by converting electrical energy into hydrogen fuel.Pt-based noble metal catalysts have been proved to be the most effective ones for hydrogen evolution reaction（HER）but their high cost and low abundance limit their commercial potentials.Therefore,high-performance,cost-effective and earth-abundant non-noble metal substitutes shine on the stage.We design and construct Ni and Co-based electrocatalysts with high performance to enable widespread demand of clean energies.These catalysts are obtained via nitridation,hydrogen reduction,electrodeposition and in-suit transformation and characterized by X-ray diffractometer,scanning electron microscopy,transmission electron microscopy and X-ray photoelectron spectroscopy and so on.Their HER performances are carefully investigated.The main research contents of this dissertation are shown as follows:1.In this chapter,3D Ni₃N-CeO₂ nanohybrid coated on Ti mesh（Ni₃N-CeO₂/TM）is reported as a high-performance catalyst for electrochemical alkaline hydrogen evolution reaction.We carefully investigate the interfacial synergy between Ni₃N and CeO₂.Due to the beneficial mass transportation and high electrical conductivity,as well as the interfacial synergy between Ni₃N and CeO₂,Ni₃N-CeO₂/TM exhibits high electrocatalytic activity and long-term durability.This work can benefit the development and construction of non-precious electrocatalysts with high performance for practical applications.2.In this chapter,we first prepare NiO-CeO₂ nanosheet array supported on Ti mesh（NiO-CeO₂/TM）via hydrothermal reaction followed by annealing,then make NiO-CeO₂/TM as a precursor to construct Ni-CeO₂ nanosheet array（Ni-CeO₂/TM）through H₂ reduction.The property of 3D porosity makes more active sites be exposed,which benefits the progress of catalytic reaction.Ni-CeO₂/TM can serve as an excellent and stable electrocatalyst toward alkaline hydrogen evolution reaction.To afford a current density of 10 mA cm^–2in 1 M KOH solution,Ni-CeO₂/TM requires overpotential as low as 67 mV,77 mV lower than that of Ni/TM.Furthermore,the electrocatalyst shows excellent electrochemical durability with nearly 100%Faradaic efficiency（FE）.3.In this chapter,bimetallic Co-Mo-B film on Ti mesh（Co-Mo-B/Ti）is designed and fabricated via one-step electrodeposition,which exhibits a dramatically enhanced HER performance in alkaline media.We carefully investigate the influence of deposition time and atomic ratio of Co/Mo on the properties of the as-prepared catalysts.To attain a current density of 20 mA cm^–2,the ideal Co-Mo-B/Ti only demands overpotential of 110 mV,190 mV less than the counterpart for Co-B/Ti,with strong electrochemical durability to maintain its catalytic activity for at least 32 h.4.An electrocatalyst with core-shell structure is constructed and fabricated via in situ transformation in this chapter.Firstly,CoAl-LDH nanoarray（LDH）supported on Ti mesh（LDH/TM）is prepared by hydrothermal reaction,then a bias is applied to construct LDH@Al-Co-P/TM core-shell structure via in situ transformation.LDH@Al-Co-P/TM as an electrocatalyst displays excellent HER activity in neutral media（1 M PBS）.When the current density reaches 10 mA cm^–2,only 150 mV overpotential is needed.Remarkably,this catalyst also shows strong long-term electrochemical durability with its activity being maintained and achieves nearly 100%FE.This work not only offers a new strategy for preparing high-efficiency electrocatalyst toward neutral HER,but also provides valuable guidance for constructing amorphous phosphide with array-structure using facial and green method.