02688nas a2200337 4500008004100000022001400041245014200055210006900197260000800266490000700274520145100281653004201732653003801774653002701812653003601839653003601875653002801911653002301939100002001962700003001982700002702012700003002039700002702069700002402096700002102120700001802141700001802159700002602177700002402203856012302227 2023 eng d a1613-681000aActive site engineering and theoretical aspects of ``Superhydrophilic'' nanostructure array enabling efficient overall water electrolysis0 aActive site engineering and theoretical aspects of Superhydrophi cDEC0 v193 a

The rational design of noble metal-free electrocatalysts holds great promise for cost-effective green hydrogen generation through water electrolysis. In this context, here, the development of a superhydrophilic bifunctional electrocatalyst that facilitates both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline conditions is demonstrated. This is achieved through the in situ growth of hierarchical NiMoO4@CoMoO4 center dot xH(2)O nanostructure on nickel foam (NF) via a two-step hydrothermal synthesis method. NiMoO4@CoMoO4 center dot xH(2)O/NF facilitates OER and HER at the overpotentials of 180 and 220 mV, respectively, at the current density of 10 mA cm(-2). The NiMoO4@CoMoO4 center dot xH(2)O/NF parallel to NiMoO4@CoMoO4 center dot xH(2)O/NF cell can be operated at a potential of 1.60 V compared to 1.63 V displayed by the system based on the Pt/C@NF parallel to RuO2@NF standard electrode pair configuration at 10 mA cm(-2) for overall water splitting. The density functional theory calculations for the OER process elucidate that the lowest Delta G of NiMoO4@CoMoO4 compared to both Ni and NiMoO4 is due to the presence of Co in the OER catalytic site and its synergistic interaction with NiMoO4. The preparative strategy and mechanistic understanding make the windows open for the large-scale production of the robust and less expensive electrode material for the overall water electrolysis.

10adensity functional theory (DFT) study10ahydrogen evolution reaction (HER)10aHydrothermal synthesis10aoxygen evolution reaction (OER)10asuperhydrophilic nanostructures10asynergistic interaction10awater electrolysis1 aBarik, Sidharth1 aKharabe, Geeta, Pandurang1 aIllathvalappil, Rajith1 aSingh, Chandrodai, Pratap1 aKanheerampockil, Fayis1 aWalko, Priyanka, S.1 aBhat, Suresh, K.1 aDevi, Nandini1 aVinod, C., P.1 aKrishnamurty, Sailaja1 aKurungot, Sreekumar uhttp://library.ncl.res.in/content/active-site-engineering-and-theoretical-aspects-superhydrophilic-nanostructure-array02762nas a2200229 4500008004100000022001400041245017600055210006900231260000800300300001400308490000600322520188200328100003002210700002702240700002002267700002702287700002402314700002102338700001802359700002402377856013102401 2023 eng d a2398-490200aCobalt-manganese modified theophrastite phase of nickel hydroxide nanoflower arrays on nickel foam as a self-standing bifunctional electrode for overall water electrolysis0 aCobaltmanganese modified theophrastite phase of nickel hydroxide cMAY a2428-24400 v73 a

Designing and developing self-supported electrodes for water electrolysis is attractive as compared to conventional catalyst-coated electrodes. Herein, a (Co0.3Mn0.1Ni0.6)(OH)(2)/NF nanocomposite is prepared by anchoring (Co0.3Mn0.1Ni0.6)(OH)(2)via simple one-pot hydrothermal synthesis on nickel foam. The presence of Mn induces the external electronic structure of Co(OH)(2), and this also improves the electrochemically active surface area (ECSA). These favor better accessibility of active sites and increased intrinsic activity for the OER and HER. (Co0.3Mn0.1Ni0.6)(OH)(2)/NF has shown promising electrochemical activity toward the OER and HER in a 1 M KOH electrolyte, with an overpotential of 270 mV for the OER and 163 mV for the HER to deliver 10 mA cm(-2) current density. The overall water splitting was performed by employing (Co0.3Mn0.1Ni0.6)(OH)(2)/NF as both the cathode and anode by displaying a voltage of 1.62 V at 10 mA cm(-2), which is comparable to that extracted from a similar system based on the state-of-the-art Pt/C@NF cathode and RuO2@NF anode (1.60 V at 10 mA cm(-2)) standard electrode pair. Interestingly, at high current densities, the (Co0.3Mn0.1Ni0.6)(OH)(2)/NF//(Co0.3Mn0.1Ni0.6)(OH)(2)/NF system displayed better overall water splitting performance (1.78 V at 100 mA cm(-2)) compared to its Pt/C@NF//RuO2@NF (1.89 V at 100 mA cm(-2)) counterpart while displaying a stable output during the evolution period that lasted for 24 h. The amounts of H-2 and O-2 produced are estimated to be 701.2 and 358.6 mmol, respectively, at a time interval of 1 h; these amounts correspond to an similar to 1 : 2 ratio of O-2 and H-2, respectively. This study confirms the capability for employing (Co0.3Mn0.1Ni0.6)(OH)(2)/NF as a bi-functional and self-standing electrode for the realistic demonstrations of overall water splitting applications.

1 aKharabe, Geeta, Pandurang1 aIllathvalappil, Rajith1 aBarik, Sidharth1 aKanheerampockil, Fayis1 aWalko, Priyanka, S.1 aBhat, Suresh, K.1 aDevi, Nandini1 aKurungot, Sreekumar uhttp://library.ncl.res.in/content/cobalt-manganese-modified-theophrastite-phase-nickel-hydroxide-nanoflower-arrays-nickel-foam03375nas a2200337 4500008004100000022001400041245023000055210006900285260000800354490000700362520209900369653000702468653002602475653001402501653002702515653001802542653003002560653003002590653003402620653003402654100003002688700002002718700003302738700001802771700002702789700002002816700001802836700003602854700002402890856012302914 2024 eng d a1613-681000aAluminium, nitrogen-dual-doped reduced graphene oxide Co-existing with cobalt-encapsulated graphitic carbon nanotube as an activity modulated electrocatalyst for oxygen electrocatalyst for oxygen electrochemistry applications0 aAluminium nitrogendualdoped reduced graphene oxide Coexisting wi cAUG0 v203 a

There is a rising need to create high-performing, affordable electrocatalysts in the new field of oxygen electrochemistry. Here, a cost-effective, activity-modulated electrocatalyst with the capacity to trigger both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) in an alkaline environment is presented. The catalyst (Al, Co/N-rGCNT) is made up of aluminium, nitrogen-dual-doped reduced graphene oxide sheets co-existing with cobalt-encapsulated carbon nanotube units. Based on X-ray Absorption Spectroscopy (XAS) studies, it is established that the superior reaction kinetics in Al, Co/N-rGCNT over their bulk counterparts can be attributed to their electronic regulation. The Al, Co/N-rGCNT performs as a versatile bifunctional electrocatalyst for zinc-air battery (ZAB), delivering an open circuit potential approximate to 1.35 V and peak power density of 106.3 mW cm-2, which are comparable to the system based on Pt/C. The Al, Co/N-rGCNT-based system showed a specific capacity of 737 mAh gZn-1 compared to 696 mAh gZn-1 delivered by the system based on Pt/C. The DFT calculations indicate that the adsorption of Co in the presence of Al doping in NGr improves the electronic properties favoring ORR. Thus, the Al, Co/N-rGCNT-based rechargeable ZAB (RZAB) emerges as a highly viable and affordable option for the development of RZAB for practical applications. This manuscript reports the development of a new bifunctional catalyst that exhibits high activity and stability under practical operating conditions. The catalyst (Al, Co/N-rGCNT) is made up of aluminium, nitrogen-dual-doped reduced graphene oxide sheets co-existing with the in situ formed cobalt-encapsulated CNT units is synthesized by a scalable pyrolysis method in an inert Ar atmosphere. The developed electrocatalyst achieved enhanced the oxygen reduction reaction (ORR) and the oxygen evolution reaction OER activity as a result of the favorable synergistic modulations and the system can serve as a process-friendly air-electrode for rechargeable zinc-air battery (RZAB). image

10aAl10aBifunctional catalyst10aDFT study10aencapsulated structure10aN-dual doping10aOxygen Evolution Reaction10aoxygen reduction reaction10arechargeable zinc-air battery10aX-ray absorption spectroscopy1 aKharabe, Geeta, Pandurang1 aBarik, Sidharth1 aVeeranmaril, Sudheesh, Kumar1 aNair, Aathira1 aIllathvalappil, Rajith1 aYoyakki, Athira1 aJoshi, Kavita1 aVinod, Chathakudath, Prabhakara1 aKurungot, Sreekumar uhttp://library.ncl.res.in/content/aluminium-nitrogen-dual-doped-reduced-graphene-oxide-co-existing-cobalt-encapsulated02935nas a2200301 4500008004100000022001400041245013700055210006900192260000800261490000700269520184900276653003702125653001802162653004202180653003002222653003002252653001702282100002002299700003002319700002902349700002502378700001802403700002002421700001802441700002602459700002402485856012402509 2024 eng d a1613-681000aBreaking the Pt electron symmetry and OH spillover towards ptir active center for performance modulation in direct ammonia fuel cell0 aBreaking the Pt electron symmetry and OH spillover towards ptir  cDEC0 v203 a

The growing interest in low-temperature direct ammonia fuel cells (DAFCs) arises from the utilization of a carbon-neutral ammonia source; however, DAFCs encounter significant electrode overpotentials due to the substantial energy barrier of the *NH2 to *NH dehydrogenation, compounded by the facile deactivation by *N on the Pt surface. In this work, a unique catalyst, Pt4Ir@AlOOH/NGr i.e., Pt4Ir/ANGr, is introduced composed of PtIr alloy nanoparticles controllably decorated on the pseudo-boehmite phase of AlOOH-supported nitrogen-doped reduced graphene (AlOOH/NGr) composite, synthesized via the polyol reduction method. The detailed studies on the structural and electronic properties of the catalyst by XAS and VB-XPS reveal the possible electronic modulations. The optimized Pt4Ir/ANGr composition exhibits a significantly improved onset potential and mass activity for AOR. The DFT study confirms the OHad species spillover by AlOOH and Pt4Ir (100) facilitates the conversion of the *NH2 to *NH with minimal energy barriers. Finally, testing of DAFC at the system level using a membrane electrode assembly (MEA) with Pt4Ir/ANGr as the anode catalyst, demonstrating the suitability of the catalyst for its practical applications. This study thus uncovers the potential of the Pt4Ir catalyst in synergy with ANGr, largely addressing the challenges in hydrogen transportation, storage, and safety within DAFCs. In this article, a versatile catalyst, Pt4Ir/ANGr, is introduced composed of PtIr alloy nanoparticles decorated on AlOOH/NGr composite. The AlOOH provides an -OH-rich surface conducive to the facile adsorption and decoration of the PtIr alloy nanoparticles and OHad species spillover from AlOOH to the Pt4Ir active center during AOR, further validating the higher experimental activity obtained in Pt4Ir/ANGr. image

10aammonia oxidation reaction (AOR)10ad-band center10adensity functional theory (DFT) study10adirect ammonia fuel cells10ahydroxyl spillover effect10aXAS analysis1 aBarik, Sidharth1 aKharabe, Geeta, Pandurang1 aSamal, Pragnya, Paramita1 aUrkude, Rajashri, R.1 aKumar, Sachin1 aYoyakki, Athira1 aVinod, C., P.1 aKrishnamurty, Sailaja1 aKurungot, Sreekumar uhttp://library.ncl.res.in/content/breaking-pt-electron-symmetry-and-oh-spillover-towards-ptir-active-center-performance02164nas a2200205 4500008004100000022001400041245012400055210006900179260000900248300001400257490000700271520139800278100002301676700003001699700002001729700001801749700002401767700003801791856012901829 2024 eng d a0887-062400aCo-incorporated N-doped micro-meso porous carbon as an electrocatalyst for oxygen reduction reaction and Zn-air battery0 aCoincorporated Ndoped micromeso porous carbon as an electrocatal cAPR  a7196-72070 v383 a

Metal-organic frameworks are considered ideal precursors for the preparation of transition-metal, heteroatom-doped carbon catalysts that are perceived to be efficient electrocatalysts for energy storage devices. Herein, we demonstrate the synthesis of ZIF-67-derived Co-incorporated N-doped porous carbon catalysts supported on high surface area microporous carbon prepared from a lotus seed shell. The combination of the two carbon catalysts in different weight ratios resulted in Co-incorporated N-doped carbon sheets with tuned surface area and porosity, enabling enhanced oxygen reduction reaction (ORR) activity in an alkaline medium. The optimized carbon catalyst ZL 600 (3:1) exhibited a half-wave potential of 0.79 V vs RHE and a limiting current density of -4.38 mA cm(-2) in 0.1 M KOH solution with higher stability and methanol tolerance. The optimized sample ZL 600 (3:1) demonstrated as a cathode in a zinc-air battery exhibited an open circuit voltage of 1.29 V with a flat discharge profile at a current rate of 10 mA cm(-2). The homemade system produced a specific capacity of 610 mAh g(-1) and a peak power density of 111 mW cm(-2), comparable to the cathode made with Pt/C. The high micro-mesoporosity, pyridinic and pyrrolic nitrogen contents, as well as enriched Co-active centers protected by carbon sheets favorably contributed to the efficient ORR mechanism.

1 aPriya, Vaishna, K.1 aKharabe, Geeta, Pandurang1 aBarik, Sidharth1 aMohamed, Peer1 aKurungot, Sreekumar1 aHareesh, Unnikrishnan, Nair Saras uhttp://library.ncl.res.in/content/co-incorporated-n-doped-micro-meso-porous-carbon-electrocatalyst-oxygen-reduction-reaction02683nas a2200205 4500008004100000022001400041245014200055210006900197260000900266300001400275490000700289520191400296100002402210700002002234700002402254700002502278700002402303700002202327856012802349 2024 eng d a0897-475600aRole of nitrogen doping in modulating ruthenium nanocatalysts for enhanced electrochemical hydrogen evolution reaction in alkaline medium0 aRole of nitrogen doping in modulating ruthenium nanocatalysts fo cAPR  a4262-42740 v363 a

Nitrogen doping has become a fundamental approach to enhance the catalytic performance of carbon materials across various applications. The introduction of nitrogen creates defects and active sites, promoting the formation of small metal particles and strengthening the metal-support interaction within carbon materials. However, the challenge lies in developing sustainable and cost-effective methods for synthesizing nitrogen-doped carbon materials. In this study, we present a sustainable approach for the synthesis of ruthenium on nitrogen-doped carbon catalysts (Ru-CCP) using chitosan as a nitrogen and carbon source. Unlike traditional methods, our process avoids the use of additional nitrogen precursors and templates, streamlining the synthesis while using a renewable resource. The synthesized material exhibits an exceptional performance in the electrochemical hydrogen evolution reaction (HER) in alkaline conditions by achieving a current density of 25 mA cm(-2) at an impressively low overpotential of 46 mV, outperforming Pt/C under similar conditions. The detailed studies on structural and electronic properties of the materials using X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM) revealed that the remarkable catalytic activity is upheld by the unique interplay between Ru delta+ and surface nitrogen moieties, notably pyridinic and pyrrolic nitrogen. Here, we demonstrate the control of particle size and electronic environment around the metal atom via the interaction of nitrogen and unravel the role of nitrogen doping in tuning the catalytic performance. In addition, this work offers insights into efficient HER catalyst design and emphasizes the potential of biomass-derived materials like chitosan in advancing clean hydrogen production for renewable energy applications.

1 aKorampattu, Lavanya1 aBarik, Sidharth1 aPandikassala, Ajmal1 aUrkude, Rajashri, R.1 aKurungot, Sreekumar1 aDhepe, Paresh, L. uhttp://library.ncl.res.in/content/role-nitrogen-doping-modulating-ruthenium-nanocatalysts-enhanced-electrochemical-hydrogen