Synthesis Of Non-noble Metal Nanomaterials And Their Electrocatalytic Properties

Recently,with the rapid development of economy and the increasingly urgent demand for environmentally friendly resources,the research on electrode materials with high electrochemical performance and catalytic activity has also developed vigorously.In this context,fuel cell,as an efficient power generation device,is recognized as one of the most important and environmentally friendly technologies for our future energy.In addition,the reduction of CO₂ to clean energy has great practical significance in energy,environment and economy.This paper is to study the electrochemical performance of multicomponent non-noble metal materials and their composites with various carbon materials in the field of cathodic catalytic oxygen reduction reaction（ORR）of fuel cells and their electrocatalytic CO₂reduction reaction（CO₂RR）.The main research contents were as follows:（1）Single or binary transition metal（M=Ni,Co,Cu,Fe）/reduced graphene oxide（rGO）nanomaterials were prepared by a simple hydrothermal method.The results of various characterization confirmed that the obtained metal nanocomposites were successfully loaded on graphene with relatively uniform particle size,and all of them show certain electrocatalytic activity to ORR.Among them,the composite Co/rGO and CoNi/rGO modified electrodes show the more positive reduction peak potential,whose limiting current densities are much larger,and electron transfer number is stable at⁴.The onset potentials are close to zero,current density and the slope of the curve are larger than those of commercial Pt/C electrode.It indicates that the Co/rGO and CoNi/rGO are two potential catalysts to ORR performance among single or binary metal composites with carbon.（2）Carbon nanotubes（CNTs）loading cobalt（Co-N/CNTs）arraies were prepared by a simple solid-state thermal phrolysis.The effects of feeding ratio and anneal temperature on the structure and electrochemical properties were investigated.The results show that,under the optimized conditions（feeding rato of 1:1 and 800℃）,the product exhibits the array morphology of N-doped loading cobalt nanoparticles with Co-N bond.All products show electrocatalytic activity to ORR,among of them,the best product modified electrode has the onset potential at-0.08V,close to the commercial Pt/C electrode.The slope is higher than that of Pt/C electrode.The electron transfer number is 3.8.Meanwhile,the catalyst also exhibits a certain catalytic to CO₂RR.The reduction products contains a certain amount of CO and CH₄appeared in the gas products.This is a potentially bifunctional catalyst.（3）CuO-CuCo₂O₄ composite hollow sphere nanomaterials were prepared by a simple hydrothermal method.Under optimized conditions（4 h）,the obtained composite modified electrode shows the best electrochemical properties,with the most positive onset potential and the highest current density in CO₂RR.The current densities in N₂ and CO₂ gas reached 18mA and 11mA.cm^-2,respectively.The liquid product obtained is ethanol at CuO-CuCo₂O₄modified electrode in CO₂RR at-0.76V with the faraday efficiency as high as 75.86%.