Controllable Regulation And Electrochemical Catalysis Performance Study Of Nano-catalyst

From the primitive society to the current information society,the global population has gradually increased,and our demand for energy has become greater and greater.At the same time,the development of information has also allowed us to enter the information society.The global carbon dioxide emissions increased by the burning of fossil fuels It is not balanced with the carbon emissions that nature can bear.This has led to an increase in the concentration of atmospheric greenhouse gases that affect global climate change,air quality,human health,and energy security.Therefore,it is urgent to find a solution to the above problems.Catalysis is critical to solving some of the most pressing energy and environmental issues,and it has shown great advantages from producing sustainable fuels to reducing fossil fuel emissions.The use of electrocatalysis in energy is mainly to convert wind energy,tidal energy and solar energy into chemical energy and store it in H2.In addition,electrocatalysis is also widely used in protecting the environment.The electrochemical conversion of carbon dioxide(CO2)is a promising strategy that can reuse the greenhouse gases emitted as a source of value-added fuel.The catalyst realization process is to stabilize the reaction intermediate along a specific reaction path,and in the simplest path,the reaction speed is accelerated by reducing the energy barrier of the short-lived transition state(the maximum energy state between the two reaction intermediates).However,since the energy of the transition state is determined by the energy barrier in the reaction,which is called the linear free energy relationship,these energy barriers mainly determine the reaction kinetics of the reaction path.The latest advances in catalyst design principles focus on activity,nanoparticle size,surface state of nanomaterials,and types of nanoparticles,which can control catalyst activity at multiple orders of magnitude,while the combination of materials science,computational science,and inorganic chemistry can quickly Found catalyst.For the present,achieving an efficient conversion system,controlling the selectivity of products,increasing the conversion rate,and reducing the required overpotential are still major challenges.Therefore,it is urgent to find a catalyst for efficient hydrogen evolution,oxygen production and carbon dioxide electroreduction.In this paper,the application of nanocatalyst in various electrocatalysis is studied by adjusting the morphology and structure of nanocatalyst,combining with some characterization methods and theoretical calculation.Several nanomaterials in this paper have shown excellent performance in electrocatalysis,such as electrolysis of water for hydrogen,electrolysis of aquatic oxygen and electroreduction of carbon dioxide.The contents of this paper are as follows:1.A series of Ir containing chlorite oxide nanomaterials R2Ir2O7(R=rare earth ions)were synthesized by sol-gel method and applied to the electrolytic water oxidation catalysis of water under acidic conditions.It was found that this kind of material showed good oxygen properties in electrolysis of aquatic products.More importantly,the intrinsic activity of this material increased significantly with the radius of R ion.Electron structure studies have shown that the increased R ion radius weakens the electron correlation in these iridium oxide.This weakening leads to the enhancement of insulator-metal transition and the covalency of the ir-o bond,which together promote the electrolytic oxygen reaction of aquatic products.2.A series of ruddlesden-popper nickel-containing perovskite catalysts LanSrNinO3n+1(n=1,2,3,and?)were synthesized to investigate the effect of size on the performance of electrolytic oxygen(OER).With the increase of dimension with n,nickel-perovskite showed enhanced OER activity.We found that reducing the electronic correlation between Ni 3d electrons by increasing their size resulted in insulator-to-metal transitions and enhanced Ni-O hybridization,both of which accelerated OER dynamics.3.A lithium embedded iridium disselenide(Li-IrSe2)was synthesized by two-step method.In the acidic,neutral and alkaline environment,it has excellent catalytic performance in electrolysis of water.The insertion of lithium on the one hand breaks the Ir-Se chemical bond in the microscopic atomic structure,on the other hand creates many holes in the macroscopic structure.It is found by theoretical calculation that the breaking of Ir-Se chemical bond regulates the free energy of hydrogen adsorption and promotes the reaction of hydrogen evolution by electrolysis.The formation of pores increases the catalytic area and makes it easier to produce IrOx on the surface,which promotes the electrolytic oxygen reaction of aquatic products.4.We synthesized a monolayer of BiO2-x nano catalyst by stripping,revealing that during the conversion of CO2 electroreduction(CO2 ER)to formic acid,the monolayer nanosheet BiO2-x was reconstructed into metal Bi.In other words,Bi metal is actually the core active phase of BiO2-x.Metal Bi nanosheets can be used as effective CO2 ER electrocatalysts with impressive activity and selectivity for CO2 conversion to formic acid.Combined with some in-situ techniques,it has been demonstrated that these oxides can be converted to Bi metals at low potentials.