02831nas a2200265   4500008004100000022001400041245012000055210006900175260000900244300001400253490000600267520190400273653002502177653001802202653001702220653003102237653003002268653002102298100002102319700002302340700003002363700001702393700002402410856013102434       2021                        eng d  a2574-096200aZinc-air batteries catalyzed using Co3O4 nanorod-supported N-doped entangled graphene for oxygen reduction reaction0 aZincair batteries catalyzed using Co3O4 nanorodsupported Ndoped   cMAY   a4570-45800 v43 a<p>The work reported here deals with the development of an efficient non-platinum electrocatalyst for electrochemical oxygen reduction reaction (ORR) through a sequential pathway involving hydrothermal treatment followed by freeze-drying to build the desired structural architecture of the catalyst. The designed catalyst (Co3O4/nitrogen-doped entangled porous 3D graphene (NEGF)), which contains Co3O4 nanorods anchored on the surface of three-dimensional (3D)-structured N-doped graphene, was found to display higher ORR activity during single-electrode testing and demonstrate a Zn-air battery (ZAB) system. Under the hydrothermal treatment at 180 degrees C, in the presence of ammonia, nitrogen was doped into the carbon framework of graphene, which subsequently formed a self-assembled entangled 3D structure of graphene after freeze-drying. The hydrothermal treatment and freeze-drying processes were found to play vital roles in tuning the morphological and structural features of the catalyst. The doped nitrogen, apart from its favorable contribution toward ORR, helped facilitate efficient dispersion of oxide nanorods on graphene. Co3O4/NEGF displayed remarkable ORR activity in 0.1 M KOH solution, as evident from the 60 mV onset potential shift compared to the state-of-the-art Pt/C catalyst and the Tafel slope value of 74 mV dec(-1) vs 68 mV dec(-1) for Pt/C. The ZAB fabricated by employing Co3O4/NEGF as the cathode catalyst was found to be an efficient competitor for the system based on the Pt/C cathode. This high performance has been credited to the controlled interplay of the governing factors such as the interfacial interactions leading to the efficient dispersion of metal oxide nanorods, increased catalyst surface area, the cooperative effect arising from the defects present in the N-doped porous 3D graphene, and the synergetic interactions operating in the system.</p>10acobalt-oxide nanorod10afreeze-drying10ahydrothermal10aN-doped entangled graphene10aoxygen reduction reaction10azinc-air battery1 aManna, Narugopal1 aSingh, Santosh, K.1 aKharabe, Geeta, Pandurang1 aTorris, Arun1 aKurungot, Sreekumar  uhttp://library.ncl.res.in/content/zinc-air-batteries-catalyzed-using-co3o4-nanorod-supported-n-doped-entangled-graphene-oxygen02682nas a2200253   4500008004100000022001400041245010100055210006900156260000900225300001400234490000600248520179900254653002602053653003302079653003102112653003302143653001802176100002102194700002302215700001802238700001702256700002402273856013102297       2022                        eng d  a2574-096200aAir-cathode interface-engineered electrocatalyst for solid-state rechargeable zinc-air batteries0 aAircathode interfaceengineered electrocatalyst for solidstate re  cJUL   a8756-87680 v53 a<p>
	Solid-state rechargeable zinc-air batteries (ZABs) are gaining interest as a class of portable clean energy technology due to their advantages such as high theoretical energy density, intrinsic safety, and low cost. It is expected that an appropriately triple-phase boundary (TPB) engineered, bifunctional oxygen reaction (OER and ORR) electrocatalyst at the air- electrode of ZABs can redefine the performance characteristics of these systems. To explore this possibility, an electrode material consisting of manganese- cobalt-based bimetallic spinel oxide (MnCo2O4)-supported nitrogen-doped entangled graphene (MnCo2O4/NEGF) with multiple active sites responsible for facilitating both OER and ORR has been prepared. The porous 3D graphitic support significantly affects the bifunctional oxygen reaction kinetics and helps the system display a remarkable catalytic performance. The air electrode consisting of the MnCo2O4/NEGF catalyst coated over the gas diffusion layer (GDL) ensures the effective TPB, and this feature works in favor of the rechargeable ZAB system under the charging and discharging modes. As an important structural and functional attribute of the electrocatalyst, the porosity and nitrogen doping in the 3D conducting support play a decisive aspect in controlling the surface wettability (hydrophilicity/hydrophobicity) of the air electrode. The fabricated solid-state rechargeable ZAB device with the developed electrode displayed a maximum peak power density of 202 mW cm(-2), which is significantly improved as compared to the one based on the Pt/C + RuO2 standard catalyst pair (124 mW cm(-2)). The solid-state device which displayed an initial charge-discharge voltage gap of only 0.7 V at 10 mA cm(-2) showed only a small increment of 86 mV after 50 h.</p>
10aair-cathode interface10abifunctional oxygen catalyst10aN-doped entangled graphene10asolid-state zinc-air battery10aspinel oxides1 aManna, Narugopal1 aSingh, Santosh, K.1 aKurian, Maria1 aTorris, Arun1 aKurungot, Sreekumar  uhttp://library.ncl.res.in/content/air-cathode-interface-engineered-electrocatalyst-solid-state-rechargeable-zinc-air-batteries