Self-Template Synthesis And Electrochemical Performance Of Cobalt-Based Oxide Mesoporous Nanotubes

The excessive exploitation and using of traditional fossil fuels have caused a shortage of energy and triggered a series of environmental problems,which have a severe impact on people's health and the development of human society.Therefore,the development of new environmentally and friendly renewable energy is a good choose to deal with energy and environmental crisis.In recent decades,it has been made great progress on developing energy storage and conversion devices,especially the electrocatalytic water splitting.In this paper,we select the cobalt-based oxides porous hollow nanotubes as the object.We synthesized the inorganic-organic hybrid Co-Asp ultralong nanowires and developed self-template strategy to synthesize metal oxide mesoporous nanotubes and ultrathin sheet-based mesoporous nanotubes.Furthermore,we studied their formation mechanism and electrocatalytic performances of these mesoporous nanotubes.The main research content is covered the following parts:1.We firstly synthesized the organic-inorganic hybrid Co-Asp ultralong nanowires with smooth surface and average diameter of⁴00 nm through using L-aspartic acid as assistant,water and glycol as solvent.We also discussed the influence factor on inorganic-organic hybrid ultralong Co-Asp nanowires synthesis,such as the reaction temperature,reaction time,proportion of water and glycol and solution pH.Finally,the optimal reaction conditions were determined.2.We reported the self-template strategy of inorganic-organic hybrid ultralong Co-Asp nanowires to synthesize Co₃O₄ mesoporous nanotubes through surface oxidation,oxidation-induced transformation of Co-Asp and Kirkendall effect.Benefiting with open end and mesoporous structure,the as-prepared Co₃O₄mesoporous nanotubes showed excellent electrocatalytic oxygen evolution reaction?OER?activity.The overpotential at the current density of 10 mA/cm² and Tafel slop were 390 mV,76 mV/dec,respectively.In addition,the as-prepared Co₃O₄mesoporous nanotubes are recognized as excellent anode materials for Li-ion battery with larger the charge/discharge current and good stability.Furthermore,the self-template strategy can be also extended to synthesized not only the Ni O,NiCo₂O₄and Mn₅O₈ mesoporous nanotubes but also Co-based chalcogenides.3.We further developed the solvent-adjustable self-template strategy of inorganic-organic hybrid Co-Asp ultralong nanowires to synthesize 3D hierarchical ultrathin nanosheet-based NiCo₂O₄ and Co₃O₄@NiO core-shell mesoporous nanotubes through had justing the ratio of water in the reaction solvent.The as-converted ultrathin nanosheet-based NiCo₂O₄ mesoporous nanotubes exhibited excellent electrocatalytic OER activity with low onset potential?1.53 V?.The overpotential at the current density of 10 mA/cm² was 360 mV,and the electrocatalytic activity area?19.8 m F/m²?was twice time compared to NiCo₂O₄mesoporous nanotubes?4.75 mF/cm²?.