02327nas a2200229 4500008004100000022001400041245016800055210006900223260000800292490000700300520143400307653003201741653003001773653002301803100001801826700001701844700002701861700004001888700001701928700002401945856012801969 2022 eng d a2194-428800aInfluence of ice templating on oxygen reduction catalytic activity of metal-free heteroatom-doped mesoporous carbon derived from polypyrrole for zinc-air batteries0 aInfluence of ice templating on oxygen reduction catalytic activi cDEC0 v103 a

The development of highly active, cost-effective, and durable, noble metal-free oxygen reduction electrocatalysts is inevitable for the full-fledged implementation of fuel cells and zinc-air batteries. This work reports the synthesis of heteroatom (N, P, S)-doped metal-free mesoporous carbon-based electrocatalyst derived from polypyrrole by combining the ice templating, freeze-drying, and carbonization processes. The correlation between the structure and electrochemical activity of the polypyrrole-derived carbon-based electrocatalyst in the presence and absence of ice templating is investigated. The optimized electrocatalyst, aided by the ice-templating and freeze-drying step, shows an onset and half-wave potential (E-1/2) of 0.94 and 0.78 V vs reversible hydrogen electrode, respectively, in an alkaline electrolyte (0.1 m KOH). Later, the application of the optimized electrocatalyst is demonstrated in a primary zinc-air battery (ZAB) cell. The results prove that the ZAB device performance based on the homemade catalyst is on par with that of the state-of-the-art Pt/C cathode. The catalyst performance is correlated with the heteroatom doping and the enhanced porosity of the sample benefitted from ice templating. Ultimately, this work depicts a facile and rational synthesis of a truly metal-free electrocatalyst for the primary ZABs that can be a potential replacement for state-of-the-art systems.

10ametal-free electrocatalysts10aoxygen reduction reaction10azinc-air batteries1 aKurian, Maria1 aGhosh, Meena1 aVijayakumar, Vidyanand1 aPuthiyaveetil, Priyanka, Pandinhare1 aTorris, Arun1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/influence-ice-templating-oxygen-reduction-catalytic-activity-metal-free-heteroatom-doped02683nas a2200217 4500008004100000022001400041245012900055210006900184260000800253490000600261520186200267653003002129653003002159653004302189100002402232700001802256700002802274700001702302700002402319856012202343 2024 eng d a2366-748600aAdvanced 3D network of N-doped graphitic carbon with FeNi alloy embedding for high-performance rechargeable Zn-air batteries0 aAdvanced 3D network of Ndoped graphitic carbon with FeNi alloy e cJUL0 v83 a

Despite the significant progress in Zn-air batteries (ZABs), their widespread use in the rechargeable sector is hindered due to the scarcity of efficient bifunctional oxygen catalysts that can catalyze both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). To address this, an ORR/OER bifunctional electrocatalyst is designed with ultrafine alloyed FeNi nanoparticles encapsulated in a 3D interconnected N- doped carbon network structure, featuring a carbon nitride backbone enclosed in graphitic carbon. The FeNi electrocatalyst (3DFeNiPDC) showed good bifunctional activity toward both ORR and OER in the basic medium with a low overpotential value of 30 mV for ORR and 6 mV for OER compared to its state-of-the-art counterparts Pt/C, and RuO2, respectively. Utilizing 3DFeNiPDC in a rechargeable Zn-air battery (RZAB) yields an open circuit voltage (OCV) of 1.35 V, a maximum power density of 232 mW cm-2, and an energy density of 707 W h kg-1. Additionally, a flexible RZAB employing 3DFeNiPDC demonstrates an OCV of 1.4 V with various bending angles. These finding suggest 3DFeNiPDC as a viable alternative to noble metal-based RZABs, offering superior bifunctional electrocatalytic activity and stability, particularly with its enhanced air-breathing properties facilitating improved operability under practical conditions. The bifunctional electrocatalytic activity of FeNi alloy nanoparticles embedded in a 3D- interconnected N-doped graphitic carbon (3DFeNiPDC) for both oxygen reduction and oxygen evolution is studied. The 3D architecture and core-shell characteristics of FeNi alloy nanoparticles provide better activity and stability for oxygen electrocatalysis. The electrocatalytic activity of 3DFeNiPDC has been exploited for liquid-state and solid-state flexible rechargeable zinc-air batteries. image

10aOxygen Evolution Reaction10aoxygen reduction reaction10arechargeable flexible zinc-air battery1 aPandikassala, Ajmal1 aKurian, Maria1 aGangadharan, Pranav, K.1 aTorris, Arun1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/advanced-3d-network-n-doped-graphitic-carbon-feni-alloy-embedding-high-performance02297nas a2200253 4500008004100000245015700041210006900198260000800267300001100275490000600286520134700292653003301639653003001672653003001702653003401732100001801766700001701784700002401801700002001825700002001845700002601865700002401891856012801915 2026 eng d00aElucidating the oxygen electrocatalytic activity of chromium cobalt spinel oxide supported over the spherical carbon for rechargeable zinc-air batteries0 aElucidating the oxygen electrocatalytic activity of chromium cob cMAY ae703360 v93 a

Cr1.5Co1.5O4 spinel nanoparticles supported over 3D spherical carbon (Cr1.5Co1.5O4/C-800) is synthesized as a bifunctional electrocatalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) for rechargeable zinc air battery (RZAB) applications. The incorporation of Cr into the spinel lattice and the decoration of the active material on a 3D spherical carbon support with intrinsic ORR activity and superior electrical conductivity enable uniform distribution of catalytically active sites, thereby improving bifunctional catalytic activity. The DFT studies were conducted to understand the role of the Cr in modulating the catalytic sites of the active material and to elucidate its effect on tuning the Co sites to enhance the activity. Half-cell studies show that Cr incorporation and spherical carbon support synergistically enhanced catalytic activity, with the Cr1.5Co1.5O4/C-800 catalyst demonstrating an onset potential of 0.93 V (70 mV lower than Pt/C) and an E & half; value of 0.70 V for ORR and an overpotential of 0.369 V at 20 mA cm-2 (eta 20) for OER (0.375 V for the RuO2 catalyst). The catalyst's bifunctional activity was validated in an RZAB, where it outperformed the Pt/C-RuO2 benchmark, delivering superior rate capability and stability and achieving a cycling life exceeding 145 h.

10achromium cobalt spinel oxide10aOxygen Evolution Reaction10aoxygen reduction reaction10arechargeable zinc-air battery1 aKurian, Maria1 aAmin, Seerat1 aPandikassala, Ajmal1 aManoj, Malavika1 aVijayan, Jubina1 aKrishnamurty, Sailaja1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/elucidating-oxygen-electrocatalytic-activity-chromium-cobalt-spinel-oxide-supported-over