Preparation And Oxygen Reduction Performance Of Zirconia Carbon-based Composites

Benefiting from low cost,low toxicity,rich resources,and high specific densities,metal-air batteries are believed to an important direction for future battery development.However,the development of metal-air batteries still face hardships such as slow oxygen reduction kinetics,poor reversibility,and poor durability.Therefore,improving the high efficiency of catalysts is a"sharp weapon"for metal-air batteries to enter practical applications.In this paper,the influcences of composition and electronic structure of carbon-based zirconate on oxygen reduction reaction mechanism and electrochemical performance are discussed.The main work is as follows:（1）Experimental and theoretical research on the performance of ZrO₂/NC catalyst;（2）Study on the performance of Fe on ZrO₂/NC catalyst.The following is the specific research content:（1）Monoclinic ZrO₂/NC catalyst was prepared by the sol-gel method.Using electrostatic self-assembly between surfactant CTAB and metal ions to form basic building blocks to encapsulate nitrogen atoms and metal ions,porous catalysts with high nitrogen and high zirconium content were obtained.Test results show that when the ratio of Zr Cl₄ to CTAB is 1:3,the measured half-wave potential(E_1/2=0.815 V)of ZrO₂/NC catalyst in 0.1 M KOH solution is the same as that of commercial Pt/C catalyst.And BET is 787.3 m²/g.The formation of O-Zr-N structure enhances the conductivity and stability of ZrO₂/NC catalyst.Herein,the aging test for 1000 cycles shows that the half-wave potential of ZrO₂/NC catalyst decreases by 25 m V,which is 8 m V less than that of Pt/C catalyst(ΔE_1/2=-33 m V).Theoretical calculations show that the stability of theZrO₂/NC catalyst mainly comes from the hybridization of theZr-p orbital and the N-p orbital,which reduces the energy of the bonding orbital.The study provides a new design idea for ZrO₂to become a new type of oxygen reduction catalyst.（2）Monoclinic FeZrO₂/NC catalyst was prepared by the sol-gel method.With Fe and Zr salts participating in the self-assembly process,the gel structure of FeZr coexisting was successfully prepared.This reaction precursor was further pyrolyzed to achieve FeZrO₂/NC catalyst.Stability test result shows that after 1000 laps CV scanning,the half-wave potential of FeZrO₂/NC catalyst only drops by 11 m V,and the stability is obviously improved,the strong synergistic effect between doped Fe and Zr is the key to increase its stability.This provides a simple new method for adjusting the electronic structure of metal oxide and improving the alloy zirconium-based catalyst by adjusting the structure and performance.