Preparation Of Non-metallic Doped Iron Coordination Catalyst And Its Application In Zinc-CO₂ Battery

Since the industrialization on the 19th century,Fossil fuels are consumed in large quantities which led to excessive CO₂emissions and a sharp increase in the greenhouse effect.However,the global demand for energy is still increasing,so it is urgent to develop new environmentally friendly energy to replace fossil fuels.At present,human beings have made great progress in wind energy,solar energy and hydroelectric energy,but these technologies are restricted by region and climate.The development of zinc-carbon dioxide battery has brought the opportunity to deal with both environmental and energy problems,but there are several key problems:Firstly,when charging and discharging,oxygen evolution reaction（OER）and carbon dioxide reduction reaction（CO₂RR）occurred at the cathode respectively,which had a slow kinetic process and a high over potential.Secondly,the cathode catalyst is unstable at OER and CO₂RR potentials during charging and discharging.Thirdly,maintaining high selectivity of carbon dioxide reduction products is a problem that needs to be solved.Based on these problems,it is very important to design and prepare a stable,cheap and efficient OER/CO₂RR bifunctional catalyst for the cathode of zinc-carbon dioxide battery.In this paper,a series of bifunctional catalysts with high efficiency and stable oerco2rr activity have been synthesized on a metal organic framework（MOF）with high specific surface area and uniform site distribution by the coordinated environment of nonmetal iron,and the mechanism of the catalyst in the zinc-carbon dioxide battery was studied systematically.Porous Carbon Materials（Fe-SA/BNC）anchored to B,N codoped with Fe were prepared by aqueous-phase method based on ZIF-8 precursor,which showed excellent CO₂RR properties.The reduction efficiency of CO was up to 94%at-0.7 v（V vs.RHE）potential.The discharge current density of the aqueous zinc-carbon dioxide battery based on this material is as high as 1.18 m A cm^-2,in addition,the theoretical calculation indicates that the impurity of B is beneficial to inhibit the hydrogen evolution reaction,so we use membrane electrode assembly（MEA）to achieve up to130 m A/cm^-2current and 99%FE_COat 100 m A/cm^-2.Fe-P Nanocrystals were synthesized by methanol-phase method based on the precursor of Zif-8,a kind of zeolite framework material（Fe-P@NCPs）.The material shows excellent selectivity in catalytic reduction of CO（CO₂RR）from CO₂,and its Faraday efficiency(FE_CO)is as high as 95%at-0.55 v（V vs.RHE）potential,at the same time,its peak power density of 0.85 m A cm^-2is better than most non-noble metal catalysts reported so far in the test of Zn-CO₂battery,the charge-discharge potential of Fe-p@NCPs has no obvious attenuation.