Porous Co-based Spinel Materials Prepared By Template Method And Their Electrocatalytic Properties

With the development of the society and the increasing population,our demand for fossil fuels?coal,oil,natural gas?is increasing,resulting in more and more obvious problems such as energy shortage and environmental pollution.It is essential to excavate renewable energy for the sustainable development of the society.Among them,the electrochemical method to convert water,carbon dioxide,nitrogen,hydrocarbons,ammonia and other small molecules into usable fuels is one of the most promising and effective methods in current research.However,reactions such as oxygen reduction?ORR?,oxygen evolution?OER?,hydrogen evolution?HER?,carbon dioxide reduction?CRR?,nitrogen reduction?NRR?and urea redox?UOR?have slow kinetics.Therefore,it is important to develop efficient electrocatalysts to improve the activity,selectivity and durability of these reactions.Oxygen evolution reaction?OER?is a half reaction of water splitting.As it involves a four-electron transfer process the reaction process is slow.It is important to find the right catalyst to reduce the overpotential for the use of clean energy.Generally,precious metals catalysts have better properties.Pt is considered as the best catalyst of ORR and HER.IrO₂ and RuO₂ are the excellent OER catalyst so far.But its exorbitant price limits its application.It is of great significance for the application of the next generation of energy technology to realize the diversification of electrochemical application by replacing the catalysts of noble metals with abundant earth resources catalysts.Many methods have been reported to improve the OER of the spinel,but further research is needed to improve the OER property by regulating the structure and electronic state of the catalysts.In this paper,porous spinel Co₃O₄ and Fe-doped Co₃O₄were prepared by the template method and the changes of spinel structure and electronic state caused by Fe doping were discussed:Fe entered different sites of spinel,making the valence and electronic state changes of Fe and Co and exploring the structure-activity relationship.In this paper,porous spinel Co₃O₄,Al-Co₃O₄,In-Co₃O₄ were synthesized by template method:Al and In are located in the periodic table of the elements in the first?A tribe,and no d electron orbital,the radius r _In>r _Al.We found that OER properties of the sample were better as the ion radius increased.The OER performance of the sample was In-Co₃O₄>Co₃O₄>Al-Co₃O₄.Since the ion radius of Co₃O₄ increased,resulting in lattice expansion and strain increase and thus OER performance changed.In this paper,a series of Co based spinel materials with porous structure,such as Co₃O₄,Fe-Co₃O₄,Al-Co₃O₄,In-Co₃O₄ doped with different ions were prepared by the template method,and the relationship between structure and performance was explored,providing a new idea for the preparation of electrocatalyst.