02198nas a2200241 4500008004100000022001200041245012300053210006900176260000800245300000700253490000800260520135300268653002501621653001601646653002801662653002001690100002701710700002901737700001601766700001501782700003001797856012901827 2018 eng d a974362600aSubtle interaction between Ag and O 2 : a near ambient pressure UV photoelectron spectroscopy (NAP-UPS) investigations0 aSubtle interaction between Ag and O 2 a near ambient pressure UV cMAR a300 v1303 aThe Ag-O2 interaction, which is at the center-stage of Ag-catalyzed partial oxidation reactions, is studied with NAP-UPS up to 0.2 mbar O2 pressure between 295 and 550 K. Three temperature regimes were identified for distinct Ag-O2 interaction, which are (a) 295–390 K, where mainly dissociative chemisorption of O2 happens, (b) 390–450 K, where diffusion of O-atoms into the sub-surfaces of Ag is prominent, and (c) >450 K, where metastable oxide forms on polycrystalline Ag surfaces. The work function (WF) of Ag changed from 4.95 (≤390 K) to 5.30 eV (390–450 K), and then to 5.7 eV (≥450 K) at 0.1 mbar O2 pressure. Oxygen population in the sub-surfaces imparts crucial modifications to Ag at 390–450 K; it makes the surface to be electron-deficient that relates to the change in the WF of Ag and facilitates the formation of space charge layer on Ag surface. Oxygen adsorbed on such modified Ag-surfaces is electrophilic in nature, and this appears at a higher binding energy in core level XPS than the chemisorbed oxygen on metallic Ag. This is supported by angle-dependent NAP-XPS studies. The subsurface population of oxygen in Ag no longer persists at >410 K when the O2 supply is removed. A high ratio of antibonding/bonding O 2p bands suggests the unique silver-oxygen interaction under the measurement conditions.10aElectronic Structure10aepoxidation10aheterogeneous catalysis10aSurface Science1 aGhosalya, Manoj, Kumar1 aReddy, Kasala, Prabhakar1 aJain, Ruchi1 aRoy, Kanak1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/subtle-interaction-between-ag-and-o-2-near-ambient-pressure-uv-photoelectron-spectroscopy02042nas a2200217 4500008004100000022001400041245012900055210006900184260000900253300001400262490000700276520126400283653002601547653002501573653002801598653001401626653000801640100001601648700003001664856013001694 2020 eng d a1867-388000aElectronic structure evolution of Pd@Co nanocatalysts under oxidation and reduction conditions and preferential CO oxidation0 aElectronic structure evolution of PdCo nanocatalysts under oxida cAUG  a4176-41840 v123 a

Herein, we present the surface electronic structure and morphological evolution under reduction and oxidation conditions for Pd@Co (PC) core-shell nanoparticles with different Pd : Co ratio (PC=2 : 1, 1 : 1 and 1 : 2). Extensive measurements have been made with NAPXPS (near ambient pressure x-ray photoelectron spectroscopy) under oxidising and reducing conditions, and ex-situ HRTEM. It has been demonstrated that PC catalysts are thermally stable towards morphological changes, at least up to 575 K. Nonetheless, it shows a significant surface electronic structure changes under reaction environments, which are highly relevant to heterogeneous catalysis. As expected, high (low) population of metallic (oxidised) Co was observed, while retaining core shell structure under reduction (H(2)and vacuum annealing) environment. Interestingly, the Pd-Co metallic interface helps to overcome the pyrophoric nature of cobalt and stabilised a significant amount of metallic Co at Pd-Co interface even in the presence of 0.1 mbar O(2)up to 575 K. The presence of Pd-Co and Pd-Co@Co(3)O(4)interfaces in reaction environment makes the catalyst dual functional. The proof of concept has been explored in terms of oxidation of CO in the presence of H(2)or O-2.

10aCore-Shell morphology10aElectronic Structure10aheterogeneous catalysis10ainterface10aXPS1 aJain, Ruchi1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/electronic-structure-evolution-pdco-nanocatalysts-under-oxidation-and-reduction-conditions02295nas a2200217 4500008004100000022001400041245016500055210006900220260000800289300001100297490000800308520148300316653003001799653002501829653002301854653001601877100001501893700001801908700002201926856012901948 2020 eng d a0925-838800aInvestigating effect of strain on electronic and optical properties of lead free double perovskite Cs2AgInCl6 solar cell compound: A first principle calculation0 aInvestigating effect of strain on electronic and optical propert cMAR a1527580 v8173 a

Despite serious problems associated with toxicity of lead, lead halide perovskite based solar cells have resulted with remarkable efficiency and hence gained much interest. To overcome this aspect, numerous solutions are attempted by researchers which include the development of new environmental friendly lead free double perovskite (DP) photovoltaic materials. Enlightening on the same line, we report first principle calculations on electronic and optical properties of Cs2AgInCl6 solar photovoltaic materials. Present opto-electronic computations for lead free DP compound, have been performed using the full potential linearized augmented plane wave method. In present investigations, we have adopted exchange and correlation potentials prescribed by Perdew et al. and the most accurate Tran-Blaha modified Becke-Johnson. Both exchange and correlation potential computations are performed with and without spin orbit coupling. Results obtained for electronic and optical properties are validated by systematic comparison with available experimental data. Reasonable reconciliation between investigated results and the available experimental data, endorse accuracy of present computations. To identify the effect of strain on energy gap and hence on the optical properties of Cs2AgInCl6 compound, computations of electronic and optical properties have also been performed under the different values of strain application. (C) 2019 Elsevier B.V. All rights reserved.

10aDensity functional theory10aElectronic Structure10aOptical properties10asolar cells1 aSoni, Amit1 aBhamu, K., C.1 aSahariya, Jagrati uhttps://library.ncl.res.in/content/investigating-effect-strain-electronic-and-optical-properties-lead-free-double-perovskite01630nas a2200265 4500008004100000022001400041245013100055210006900186260000800255300001400263490000600277520070900283653002500992653003201017653003001049653001501079653002001094100001901114700001901133700001801152700001801170700002001188700002501208856013101233 2020 eng d a2574-096200aStress-induced electronic structure modulation of manganese-incorporated Ni2P leading to enhanced activity for water splitting0 aStressinduced electronic structure modulation of manganeseincorp cFEB a1271-12780 v33 a

The cornerstone of the emerging hydrogen economy is hydrogen production by water electrolysis with concomitant oxygen generation. Incorporating a third element in metal phosphides can tune the crystalline and electronic structure, hence improving the electrocatalytic properties. In this work, Mn-doped Ni2P with varying ratios of Mn and Ni has been explored as excellent catalysts for water splitting. A complete cell made of the best catalyst Ni1.5Mn0.5P electrodes showed low voltage of 1.75 V at a current density of 10 mA cm(-2) due to enhanced electrical conductivity, induction of tensile stress, enhanced electrochemical surface area, and increased electric dipole upon Mn incorporation.

10aElectronic Structure10ahydrogen evolution reaction10aOxygen Evolution Reaction10aphosphides10awater splitting1 aSarkar, Shreya1 aDheer, Lakshay1 aVinod, C., P.1 aThapa, Ranjit1 aWaghmare, Umesh1 aPeter, Sebastian, C. uhttps://library.ncl.res.in/content/stress-induced-electronic-structure-modulation-manganese-incorporated-ni2p-leading-enhanced02382nas a2200241 4500008004100000022001400041245017800055210006900233260000800302490000700310520149900317653000801816653002101824653002501845653000801870653002401878100002101902700001801923700002001941700002401961700003101985856012402016 2025 eng d a1616-301X00aDesign and synthesis of PtPdNiCoMn high-entropy alloy electrocatalyst for enhanced alkaline hydrogen evolution reaction: a theoretically supported predictive design approach0 aDesign and synthesis of PtPdNiCoMn highentropy alloy electrocata cAPR0 v353 a

Electrocatalytic hydrogen generation requires a cutting-edge, multifunctional electrocatalyst with abundant active sites to drive multielectron transfer reactions. High entropy alloys (HEA) are complex five or more-element alloy systems with high configurational entropy which makes them unique materials for next-generation electrocatalysts. Here, in this work, based on new screening guidelines for catalyst selections that combine density-functional theory calculated Gibbs formation-enthalpy with bond length and electronegativity variance, a novel HEA electrocatalyst consisting of five elements, namely, Pt, Pd, Ni, Co, and Mn is designed. By simple room temperature electrodeposition, the designed catalyst is prepared and its hydrogen evolution reaction (HER) is explored and validated through experimental and theoretical approaches. The HEA demonstrated a superior HER activity with an overpotential of 22.6 mV at -10 mA cm-2 which outperforms Pt/C commercial catalyst. No evident degradation of the material is detected even after 100 hours of continuous operation under high current density. Moreover, the HEA has shown exceptional performance in harsh electrolyte conditions such as in simulated seawater and actual seawater. Remarkably, the density-functional theory calculated small Gibbs formation-enthalpy (approximate to 0 eV) compared to Pt/C places the new HEA near the apex of Trasatti's model of Volcano plot, which is also suggestive of superior HER activity.

10aDFT10aelectrocatalysts10aElectronic Structure10aHER10ahigh-entropy alloys1 aChandran, Athira1 aDutta, Pritha1 aSingh, Prashant1 aSingh, Ashutosh, K.1 aPrasad, Bhagavatula, L. V. uhttps://library.ncl.res.in/content/design-and-synthesis-ptpdnicomn-high-entropy-alloy-electrocatalyst-enhanced-alkaline