02643nas a2200265 4500008004100000245012200041210006900163260000900232300001400241490000600255520168400261653002901945653003401974653002102008653003002029653002502059653003002084100001902114700002302133700002802156700002402184700002402208700002102232856012402253 2021 eng d00aSeed-mediated growth of Pt on high-index faceted Au nanocrystals: the ag lining and implications for electrocatalysis0 aSeedmediated growth of Pt on highindex faceted Au nanocrystals t cSEP  a9155-91660 v43 aBimetallic Au@Pt nanocrystals (NCs) offer a unique combination of plasmonic and catalytic properties and are a growing field of research. Herein, we report an unusual observation in the behavior of silver ions (Ag+) which was found to play a dominant role in dictating the Pt deposition in a seed-mediated growth method. `While the literature is replete with various instances of Ag-assisted Pt deposition whereby higher concentration of Ag+ translates into a thicker Pt shell, in the present study, contradictory observations were made. In the presence of lower amounts of Ag+, thick Pt shells were visualized, while at higher concentrations of Ag+, the extent of Pt deposition via the galvanic replacement reaction was reduced. Additionally, the presence of Ag was deemed necessary for the Pt deposition to take place, either in the form of an underpotential deposition layer on the Au NCs or by introducing Ag+ in the growth solution. We have demonstrated our findings on two different Au NCs enclosed with high-index facets, concave cuboid, and elongated tetrahexahedra, which mirror similar observations and provide generality to our claim. To the best of our knowledge, the time required for Pt deposition on the Au core in the present work is the least among the reported seed-mediated routes. Furthermore, this work, besides presenting a facile and general route for the amalgamation of catalytic and plasmonic properties in hybrid Pt-Au NCs, sheds light on the mechanistic aspects of Ag-assisted wet-chemical generation of bimetallic Au@Pt NCs. The overall electrocatalytic performance of our Au@Pt NCs toward the oxygen reduction reaction was realized to be impressive.10abimetallic nanostructure10agalvanic replacement reaction10ahigh-index facet10aoxygen reduction reaction10aseed-mediated growth10aunderpotential deposition1 aRoy, Debashree1 aRajendra, Ranguwar1 aGangadharan, Pranav, K.1 aPandikassala, Ajmal1 aKurungot, Sreekumar1 aBallav, Nirmalya uhttp://library.ncl.res.in/content/seed-mediated-growth-pt-high-index-faceted-au-nanocrystals-ag-lining-and-implications02705nas a2200265 4500008004100000022001400041245013400055210006900189260000900258300001400267490000700281520178300288653001802071653002002089653001402109653002102123653001702144653002002161653002202181653003002203100002802233700002402261700002402285856013002309 2021 eng d a1944-824400aToward pH independent oxygen reduction reaction by polydopamine derived 3D interconnected, iron carbide embedded graphitic carbon0 aToward pH independent oxygen reduction reaction by polydopamine  cFEB  a8147-81580 v133 a

Recent advancements on the development of nonprecious electrocatalysts with iron (Fe) incorporated active centers have generated confidence on realizing cost-effective proton exchange membrane fuel cells (PEMFCs). However, most of these catalysts that emerged as a substitution for the platinum supported on carbon (Pt/C) catalysts in oxygen reduction reaction (ORR) are active under basic conditions, and their feasibility in PEMFCs remains as a challenge. In this scenario, this work reports the synthesis of a Pt-free oxygen reduction electrocatalyst prepared by the annealing of polydopamine grown melamine foam. The prepared catalyst has a three-dimensional (3D) interconnected bilayer network structure possessing the carbon nitride backbone wrapped by graphitic carbon layer bearing iron carbides and nitrides as the active centers (3DFePDC). Interestingly, the 3D-FePDC catalyst displayed an ORR activity both under acidic and basic conditions. Whereas the ORR performance of 3D-FePDC closely matches that of the commercial Pt/C in the basic medium, it displays only a low overpotential value of 60 mV under acidic conditions compared to its Pt counterpart. The kinetics of ORR on 3DFePDC is found to be similar to the four-electron (4e) reduction pathway displayed by Pt/C. Testing of a PEMFC in a single cell mode by using 3D-FePDC as the cathode catalyst and Nafion membrane delivered a maximum power density of 278 mW cm(-2), which is a promising value expected from a system based on the nonprecious metal cathode. Ultimately, as a cost-effective catalyst that can effectively perform irrespective of the pH conditions, 3D-FePDC offers significant prospects in the areas like fuel cells and metal-air batteries which work in acidic and/or basic conditions.

10aacidic medium10aelectrocatalyst10afuel cell10agraphitic carbon10aIron carbide10anitrogen doping10anonprecious metal10aoxygen reduction reaction1 aGangadharan, Pranav, K.1 aPandikassala, Ajmal1 aKurungot, Sreekumar uhttp://library.ncl.res.in/content/toward-ph-independent-oxygen-reduction-reaction-polydopamine-derived-3d-interconnected-iron01782nas a2200229 4500008004100000245010400041210006900145260000800214300001500222490000600237520097200243653001901215653001601234653003501250653002601285653003001311100002201341700002401363700002401387700001801411856012301429 2022 eng d00aTuning of oxygen reduction pathways through structural variation in transition metal-doped Ba2In2O50 aTuning of oxygen reduction pathways through structural variation cJAN ae2021011630 v93 aAbstract Oxygen reduction reaction (ORR) can take place either through a two-electron pathway to form H2O2 or through a four-electron pathway to form H2O. Both the reactions are important in the respective fields, viz., H2O2 production as well as fuel cell technology, and rational design of catalysts is mandatory to acquire high energy efficiency in both cases. Here, we report the structure-electrochemical property correlation of a series of perovskite related brownmillerite compounds, Ba2In0.75M0.25O5 (M=Mn/Fe/Co/Ni/Cu), synthesized by solid-state method. On transition metal doping, octahedral distortions were observed, and the highly disordered material tends to follow the 4e transfer mechanism. More symmetrical structures followed the 2e pathway to form H2O2 as the product with high peroxide selectivity. The distortion in the octahedral arrangement can be a descriptor to finetune the selectivity of the catalysts towards the 2e and 4e pathways of ORR.10abrownmillerite10aDescriptors10aElectrochemical H2O2 synthesis10aOctahedral distortion10aoxygen reduction reaction1 aThundiyil, Shibin1 aPandikassala, Ajmal1 aKurungot, Sreekumar1 aDevi, Nandini uhttp://library.ncl.res.in/content/tuning-oxygen-reduction-pathways-through-structural-variation-transition-metal-doped02155nas a2200229 4500008004100000022001400041245014800055210006900203260000800272490000600280520131300286653003301599653001501632653003001647653002401677100001801701700002001719700002401739700001501763700002401778856012301802 2023 eng d a2366-748600aPt-anchored-zirconium phosphate nanoplates as high-durable carbon-free oxygen reduction reaction electrocatalyst for PEM fuel cell applications0 aPtanchoredzirconium phosphate nanoplates as highdurable carbonfr cFEB0 v73 a

Commercially available platinum-supported carbon (Pt/C) catalysts are the most widely used oxygen reduction reaction (ORR) electrocatalysts in polymer electrolyte membrane fuel cells (PEMFCs). However, inadequate active triple-phase boundary formation and carbon oxidation in Pt/C during PEMFC operation shorten its lifetime and efficiency. In this direction, a new class of carbon-free electrocatalysts for ORR is prepared by dispersing Pt nanoparticles on ZrP (Zirconium phosphates) nanoplates. In one case (ZrP@Pt), the Pt nanoparticles are found to be closely distributed and completely covering the ZrP nanoplates, whereas in the second case (Pt/ZrP), the Pt nanoparticles selectively restrict dispersion along the edges of the support. ZrP as the support displays an intrinsic proton conductivity of approximate to 0.5 x 10(-4) S cm(-1) at 70 degrees C, with an activation energy (E-a) of 0.19 eV. Pt/ZrP shows better durability after 3000 start-stop cycles. The mass activity of Pt/ZrP is increased by 4.6 times compared to Pt/C, which exhibits a loss in mass activity by 1.37 times. The single-cell level validation of ZrP@Pt, Pt/ZrP, and Pt/C as the electrocatalysts in PEMFC at an operating potential of 0.60 V shows the achievable current densities of 0.600, 0.890, and 0.890 A cm(-2).

10acarbon-free electrocatalysts10afuel cells10aoxygen reduction reaction10azirconium phosphate1 aKumar, Sachin1 aYoyakki, Athira1 aPandikassala, Ajmal1 aSoni, Roby1 aKurungot, Sreekumar uhttp://library.ncl.res.in/content/pt-anchored-zirconium-phosphate-nanoplates-high-durable-carbon-free-oxygen-reduction02682nas a2200217 4500008004100000022001400041245012900055210006900184260000800253490000600261520186200267653003002129653003002159653004302189100002402232700001802256700002802274700001702302700002402319856012102343 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 uhttp://library.ncl.res.in/content/advanced-3d-network-n-doped-graphitic-carbon-feni-alloy-embedding-high-performance02588nas a2200325 4500008004100000022001400041245014000055210006900195260000800264490000700272520142200279653002001701653001901721653002801740653002801768653003001796653003901826653001601865653001801881653005001899100002201949700002401971700002701995700002402022700001802046700002602064700001802090700002402108856013002132 2025 eng d a1613-681000aHot injection assisted electronically modulated twin and grain boundary rich sub-2 nm pt3co alloy resistant to phosphate ion for PEMFCs0 aHot injection assisted electronically modulated twin and grain b cMAY0 v213 a

Modulation of the electronic d-band center, structural defects (line defects), and particle size of Pt3Co alloy electrocatalyst have huge significance in elevating its electrochemical oxygen reduction reaction activity. Deviating from traditional high-temperature strategies, the current work focuses on ripening these benefits by implying a simple economically viable hot-injection-assisted modified polyol process. A conclusive control over decrementing particle size starting from 2.7 to 1.3 nm, an increasing degree of strain (twin boundary), and shifting of the d-band center away from the Fermi level are obtained via varying the temperature to which the solution is injected. The catalyst prepared via the injection at 200 degrees C (Pt3Co(1.3 t,g-b)/fVC-200) has delivered an electrochemical surface area of 84 m(2) g(Pt)(-1) with the onset and half-wave potentials of 0.980 and 0.858 V, respectively, versus RHE and a limiting current of -6.0 mA cm(-2) with stability till 20k cycles. In the high-temperature proton exchange membrane fuel cell Pt3Co(1.3 t,g-b)/fVC-200-based cell has outperformed Pt/C rendering 600 mWcm(-2) under H-2-Air compared to 529 mWcm(-2) of Pt/C with 20% lower Pt loading and double the stability due to enhanced resistance toward phosphoric acid for accelerated voltage cycling. A similar enhancement is seen while employing the catalyst for low-temperature fuel cells.

10aelectrocatalyst10agrain boundary10ahot injection synthesis10amodified polyol process10aoxygen reduction reaction10aproton exchange membrane fuel cell10aPt3Co alloy10atwin boundary10avalance band X-ray photoelectron spectroscopy1 aSingh, Mayank, U.1 aJadhav, Swapnil, D.1 aShivankar, Bhavana, R.1 aPandikassala, Ajmal1 aKumar, Yogesh1 aKrishnamurty, Sailaja1 aVinod, C., P.1 aKurungot, Sreekumar uhttp://library.ncl.res.in/content/hot-injection-assisted-electronically-modulated-twin-and-grain-boundary-rich-sub-2-nm-pt3co02451nas a2200229 4500008004100000022001400041245013900055210006900194260000800263490000600271520157000277653003001847653003001877653004301907100002401950700002701974700002202001700002402023700002002047700002402067856013002091 2025 eng d a2366-748600aPt-based 3D electrocatalyst with process-friendly features for PEMFCs possessing fast activation and improved mass-transfer properties0 aPtbased 3D electrocatalyst with processfriendly features for PEM cAPR0 v93 a

Polymer-electrolyte-membrane fuel cells (PEMFCs) face the challenges like slow oxygen reduction reaction (ORR) kinetics and limited mass transport at high current densities, which affects their performance. The efficient water removal from the cathode is essential to improve oxygen diffusion. Addressing this, a catalyst is presented with platinum (Pt) nanoparticles distributed within a 3D carbon network (Pt/3DPDC) derived from the polydopamine-coated melamine foam. This unique architecture enhances Pt utilization and water management due to its high porosity and ample free spaces, providing a process-friendly feature for the electrode under PEMFC conditions. The pores and accessible texture of the 3D polydopamine derived carbon (3DPDC) framework facilitate ionomer uptake during the electrode fabrication, extending the active triple-phase boundary and improving the membrane electrode assembly (MEA) performance. The high porosity of Pt/3DPDC is mitigated by adding a small amount of commercial fuel cell catalayst (Pt/C), which maintains the effective catalyst number density per unit area by utilizing the excess porosity of the 3DPDC framework. This controlled interplay of the unique catalyst structure and spatially confined distribution of Pt/C within the Pt/3DPDC framework offers fast activation, reduced electrode flooding, and improved current densities across the operating potential window. This carefully engineered catalyst, designed through bottom-up strategies, is a promising electrocatalyst for practical PEMFC applications.

10aOxygen Evolution Reaction10aoxygen reduction reaction10arechargeable flexible zinc-air battery1 aPandikassala, Ajmal1 aNadumattuvayil, Varsha1 aSingh, Mayank, U.1 aJadhav, Swapnil, D.1 aYoyakki, Athira1 aKurungot, Sreekumar uhttp://library.ncl.res.in/content/pt-based-3d-electrocatalyst-process-friendly-features-pemfcs-possessing-fast-activation-and