Study On The Preparation Of Strontium-based Perovskite And Its Oxygen Evolution Performance

With the development of economy and society,the energy and environmental problems have become more and more serious.The development of clean and environmentally friendly energy has become a general trend.The various advantages shown by hydrogen energy have attracted attention,but the slow oxygen evolution power during the electrolysis of water.The learning process severely constrained its development,so the key is to develop and design low-cost,stable and efficient catalyst materials.In this paper,on the basis of Sr-based perovskite,by improving the structure and optimizing its microscopic morphology as the starting point to explore efficient and practical perovskite oxide oxygen evolution catalyst,the main work and conclusions are as follows:The SrCo_xFe_1-xO_3-δcatalyst was synthesized by the sol-gel method.By adding different proportions of Co in the B site,a relatively stable,smooth and porous SrCo_0.8Fe_0.2O_3-δcatalyst was obtained.In the comparison of OER performance,the SrCo_0.8Fe_0.2O_3-δafter reasonable doping has a current density of 10 mA cm^-2has an overpotential of 396 mV,and the initial overpotential of SF is 510 mV,the performance has been significantly improved,and the electrochemical specific surface area has also been greatly improved,indicating that the B-site doping of the perovskite was doped at the initial design stage.It is confirmed that a series of changes in the material caused by impurities,but due to its own specific surface area constraints,it is difficult to complete the qualitative change in performance.Herein,SrCo_0.8Fe_0.2O_3-δ（SCF-0）material is simply heated in a H₃BO₃solution to form a synthetic catalyst,exhibiting excellent OER activity.The optimized SCF（SCF-0.2）has an overpotential of 287 mV and a Tafel slope of 50 mV dec^-1at a current density of 10 mA cm^-2(the two items of SCF-0 are 396 mV and 102 mV dec^-1).Subsequent material characterization confirmed that,due to the efficient improvement of the surface morphology of the material,the smooth plane generates numerous needle-like nanoflower structures with a size of 30-50 nm,which significantly enhanced the specific surface area of the material,attributed to selective slowly dissolve out of a lot of Sr and a small amount of Fe.In addition to that,the perovskite SCF-0.2+Pt/C is used as the air cathode in the self-assembled zinc-air battery,which shows excellent peak energy density～106 mW cm^-2and charge-discharge cycle life.In particular,this simple surface modification method provides an effective optimization strategy for improving the specific surface area and OER performance of the material.On the basis of the work in the previous chapter,this method of stable surface reconstruction under mild conditions is universally verified,and the oxygen evolution performance of the catalyst is further strengthened.SCF82 is first doped with A site to improve its material properties.Active,and synthesize a representative typical perovskite La_0.2Sr_0.8Co_0.8Fe_0.2O_3-δ,and then perform surface reconstruction,the result of the surface,after surface treatment,the material characterization found that the microscopic morphology change is similar to the previous chapter,A nano-flower structure is produced,and the specific surface area of the material is increased from 8.31 m²/g to 73.70 m²/g.The optimized LSCF-B has an overpotential of 291 mV and 65 mV dec^-1at a current density of 10mA cm^-2The Tafel slope of LSCF(the two items of LSCF are 380 mV and 115 mV dec^-1respectively),which provides a new way of thinking for the surface reconstruction of materials in the future.