Preparation And Electrochemical Performance Of Porous Carbon Composite Nanomaterial

Environmental pollution and energy crisis have become two major issues that cannot be ignored by the human society.Zinc air batteries,as a new energy technology,have received high attention due to their clean and efficient characteristics.However,the relatively sluggish kinetics of oxygen reduction reaction（ORR）and oxygen evolution reaction（OER）for air cathodes bring a great challenge to the commercial process of zinc air batteries.Developing ORR and OER catalysts with high catalytic performance,good stability,and low cost has become a research hotspot in the field of zinc air batteries.In this paper,three nano-composites of Co/Co Fe@NPC,SO₄^2--Co Fe/NSCT and SO₄^2--Ni Fe/NSCT are prepared to improve the catalytic performance of ORR and OER respectively based on the research of non-precious metals（Ni,Co,Fe）and porous carbon nano-composites.This paper provides a detailed and in-depth study on the preparation technology,microstructure,catalytic performance,and mechanism of these three nano-composites.The main studies are as follows:（1）The nitrogen-doped three-dimensional porous carbon-loaded Co/Co Fe composite nanomaterial（Co/Co Fe@NPC）was prepared by using bovine bone powder as the precursor via a synthetic route combining pre-carbonization,potassium hydroxide activation and carbonization.The Co/Co Fe@NPC exhibits an ORR half-wave potential of 0.851 V which is superior than that of commercial Pt/C catalyst（0.818 V）.The primary zinc air battery based on Co/Co Fe@NPC exhibits high power density(178.6 m W·cm^-2,271.7 m W·cm^-2)and high specific capacity(823 m Ah·g _Zn^-1,10 m A·cm^-2),which are all better than Pt/C catalyst(146.9m W·cm^-2,228.4 m A·cm^-2;738 m Ah·g Zn^-1,10 m A·cm^-2).Meanwhile,Co/Co Fe@NPC shows good responsiveness,selectivity and stability in the glucose sensor.（2）The novel nitrogen-sulfur co-doped carbon nanotube-loaded cobalt-iron alloy composite nanomaterial with sulfate modification(SO₄^2--Co Fe/NSCT)was prepared by using melamine,cobalt sulfate and ferrous sulfate as precursors.The optimal composition of SO₄^2--Co₁Fe₁/NSCT exhibits an ORR half-wave potential of 0.854 V and an OER over-potential of 333 m V,which are superior than that of commercial Pt/C and Ru O₂ catalysts（0.818 V,366 m V）.The secondary zinc air battery based SO₄^2--Co₁Fe₁/NSCT exhibits high power density(162 m W·cm^-2,251 m A·cm^-2)and high specific capacity(814 m Ah·g _Zn^-1,25m A·cm^-2),which are all better than Pt/C+Ru O₂ catalyst(120 m W·cm^-2,187 m A·cm^-2;764m Ah·g _Zn^-1,25 m A·cm^-2).（3）The novel nitrogen-sulfur co-doped carbon nanotube-loaded nickel-iron alloy composite nanomaterial with sulfate modification(SO₄^2--Ni Fe/NSCT)was prepared by using melamine,nickel sulfate and ferrous sulfate as precursors.The optimal composition of SO₄^2--Ni₁Fe₂/NSCT exhibits an ORR half-wave potential of 0.842 V and an OER over-potential of 261 m V,which are superior than that of commercial Pt/C and Ru O₂ catalysts（0.818 V,366 m V）.The secondary zinc air battery based SO₄^2--Ni₁Fe₂/NSCT exhibits high power density(195 m W·cm^-2,320 m A·cm^-2)and high specific capacity(831 m Ah·g _Zn^-1,25m A·cm^-2),which are all better than Pt/C+Ru O₂ catalyst(120 m W·cm^-2,187 m A·cm^-2;764m Ah·g _Zn^-1,25 m A·cm^-2).