02821nas a2200349   4500008004100000022001400041245018300055210006900238260000800307300001400315490000600329520162200335653002201957653002001979653001201999653001402011653002402025653002402049653002402073653002102097653002002118653001702138653003002155653001602185653001402201653002702215653003402242100002402276700002302300700002402323856012402347       2017                        eng d  a2365-654900aActivity tuning of cobalt ferrite nanoparticles anchored on N-doped reduced graphene oxide as a potential oxygen reduction electrocatalyst by Zn substitution in the spinel matrix0 aActivity tuning of cobalt ferrite nanoparticles anchored on Ndop  cSEP  a7845-78530 v23 a<p><span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; background-color: rgb(248, 248, 248);">Development of highly efficient and durable ORR catalysts by using non-platinum group metals (such as Co, Fe, Mn, and Zn) is a challenging task in the forward path towards the realization of low-cost energy devices in the commercial stream. The present work deals with an effective strategy wherein an efficient Pt-free electrocatalyst for oxygen reduction reaction (ORR) is prepared by stoichiometrically substituting some fraction of Fe with Zn in cobalt ferrite and anchoring these spinel nanoparticles on nitrogen doped reduced graphene oxide (N-rGO). Zn substitution is found to be significantly altering the ratio of Fe2+/Fe3+ in the cobalt ferrite nanocrystal system with a concomitant promotional influence on its electrocatalytic activity towards ORR. The nanoparticle composition with a Co, Fe and Zn molar ratio of 1.0:1.7:0.3, represented by the formula CoFe1.7Zn0.3O4(CFZn(0.3)), supported over N-rGO has shown 10 mV and 20 mV positive shift in the onset and half-wave potentials, respectively, for ORR in 0.1 M KOH in comparison to the nanoparticles of CoFe2O4 supported over N-rGO (CF/N-rGO). The optimum Zn substitution is found to be narrowing down the difference with the state-of-the-art Pt/C for ORR by 100 and 110 mV in terms of the onset and half-wave potentials, respectively. Most significantly, the homemade catalyst is found to be clearly outperforming the Pt catalyst in terms of the limiting current density and electrochemical durability.</span></p>10aCarbon Nano-fiber10aCathod Catalyst10aCoFe2O410aEvolution10aMagnetic-properties10aMembrane fuel- Cell10aMetal-Air Batteries10aN-doped graphene10aNanocrystalline10ananocrystals10aoxygen reduction reaction10aperformance10aPlatinium10asolvothermal synthesis10aZn substituted cobalt ferrite1 aKashyap, Varchaswal1 aSingh, Santosh, K.1 aKurungot, Sreekumar  uhttps://library.ncl.res.in/content/activity-tuning-cobalt-ferrite-nanoparticles-anchored-n-doped-reduced-graphene-oxide