Adsorption And Dissociation Of O₂ On Carbon Nanotubes:A DFT Study

As a sustainable energy sources which have the property of high efficiency and low environmental impact,fuel cells have attracted increasing attention in the field of energy.Its performance crucially depends on the oxygen reduction reaction(ORR)efficiency at the cathode.Conventionally,platinum-based catalysts are used to promote the efficiency and speed of ORR.However,platinum is quite rare and expensive which inhibits the large-scale application of fuel cells.Consequently,it is essential to develop alternative catalysts to supersede platinum for the ORR in the fuel cell cathodes and achieve better efficiency.Single-walled carbon nanotubes(SWCNTs)were discovered by Iijima in 1993,and has stimulated sequential research in the field of nanotechnology since then.Over the past years,it has been shown that the physical and chemical properties of carbon nanotube can be changed by doping.Recently,we find that nickel-doped carbon nanotube could be used as a platinum-free electrode with a much better electrocatalytic activity,which may be of help to develop new effi-cient platinum-free oxygen reduction reaction catalysts.The effect of nickel doping on the adsorption and dissociation of the O2 molecule on single-walled carbon nanotube(SWCNT)is investigated using first-principles density functional theory calculations in company with the nudged elastic band(NEB).Our calculated results show that nickel doping can make it much easier for oxygen adsorbed on the SWCNT,and the chemisorption energy is high enough to alter the O-O bond.What’s more,the activation barrier for oxygen dissociation is lowered to 0.399 eV through nickel doping,which is much lower than Pt doped CNT.Our work have done here would be of help to develop platinum-free oxygen reduction reaction catalysts based on SWCNT.