01892nas a2200301   4500008004100000022001400041245016000055210006900215260000900284300001100293490000800304520086400312653001701176653002701193653002101220653001101241653003101252100001701283700002101300700002301321700001801344700001601362700002201378700002301400700001901423700001801442856013001460       2020                        eng d  a0926-337300aSpectroscopic evidences for the size dependent generation of pd species responsible for the low temperature CO oxidation activity on Pd-SBA-15 nanocatalyst0 aSpectroscopic evidences for the size dependent generation of pd   cSEP   a1189340 v2723 a<p>A comprehensive size dependent CO oxidation activity has been demonstrated for Pd-SBA-15 catalysts with Pd NPs of varying sizes such as 1-2, 4-6 and 7-10 nm. Pd-SBA-15 catalyst with smallest sized NPs (Pd-S-N) has been synthesized by modified deposition precipitation method recently developed in our lab. Pd-S-N catalyst (reduced at 400 degrees C) demonstrated CO oxidation activity with lower light off temperature (50 degrees C), clearly one of the best reported for a Pd-silica system. A detailed XPS and in-situ DRIFTS analyses further supported by XAS and DFT calculations reveal the presence of easily decomposable highvalent Pd-oxide on co-ordinatively unsaturated Pd sites (Pdcus). Weak binding of CO on Pdcus sites in small Pd NPs leaving sites for oxygen activation is attributed to the low temperature activity of Pd-S-N for CO oxidation.</p>
10aCO oxidation10ahigh-valent Pd species10aPd nanoparticles10aSBA-1510aunder coordinated Pd atoms1 aSoni, Yogita1 aPradhan, Sumanta1 aBamnia, Mahesh, K.1 aYadav, A., K.1 aJha, S., N.1 aBhattacharyya, D.1 aKhan, Tuhin, Suvra1 aHaider, M., A.1 aVinod, C., P.  uhttp://library.ncl.res.in/content/spectroscopic-evidences-size-dependent-generation-pd-species-responsible-low-temperature-co02190nas a2200277   4500008004100000022001400041245012300055210006900178260000900247300001600256490000700272520125600279653001601535653002501551653002401576653003001600653002101630100002301651700002101674700002001695700000501715700001601720700002301736700002301759856013001782       2021                        eng d  a2155-543500aDirect oxidation of cyclohexane to adipic acid by a WFeCoO(OH) catalyst: role of bronsted acidity and oxygen vacancies0 aDirect oxidation of cyclohexane to adipic acid by a WFeCoOOH cat  cSEP   a10754-107660 v113 aThis work reports the catalytic activity of the trimetallic mixed-metal oxyhydroxide WFeCoO(OH) for the direct oxidation of cyclohexane to adipic acid (AA) without the use of concentrated HNO3. WFeCoO(OH) displayed a 40% conversion of cyclohexane and a 67% selectivity to AA under relatively milder conditions of temperature (90 degrees C) and pressure (1 atm). Experimental evidence confirmed the presence of acidic, basic, and redox sites on WFeCoO(OH). The detailed investigation revealed that doping W in the Co-FeO(OH) matrix increased the amount of surface lattice oxygen (OS-L) and caused a significant surge in acidity (5.1 mmol/g). The calculated deprotonation energy of WFeCoO(OH) was 1434 kJ/mol, and the trend in acidity was WCoO(OH) < WFeCoO(OH) < FeCoO(OH) similar to CoO(OH). Energy calculations showed that WFeCoO(OH) had a high propensity to generate oxygen vacancies by the loss of either a water molecule or an oxygen atom (-132.2 or -140.9 kJ/mol, respectively). Basicity was generated due to the presence of conjugate pairs of the surface hydroxyl groups. The combined action of the trifunctional acidic, basic, and redox-active metal centers along with the oxygen vacancies was responsible for the enhanced catalytic performance.10aAdipic Acid10adeprotonation energy10ametal oxyhydroxides10amultifunctional catalysts10aoxygen vacancies1 aVernekar, Dnyanesh1 aDayyan, Mohammad1 aRatha, Satyajit1 a1 aHaider, Ali1 aKhan, Tuhin, Suvra1 aJagadeesan, Dinesh  uhttp://library.ncl.res.in/content/direct-oxidation-cyclohexane-adipic-acid-wfecoooh-catalyst-role-bronsted-acidity-and-oxygen02044nas a2200337   4500008004100000022001400041245014400055210006900199260000900268300001100277490000800288520095100296653001401247653001401261653001901275653000901294653001601303100002101319700001801340700001701358700002301375700002601398700002401424700002101448700001701469700002001486700003001506700002301536700001701559856013001576       2021                        eng d  a0926-860X00aIn-situ experimental and computational approach to investigate the nature of active site in low-temperature CO-PROX over CuOx-CeO2 catalyst0 aInsitu experimental and computational approach to investigate th  cAUG   a1183050 v6243 aPreferential oxidation (PROX) of carbon monoxide (CO) in presence of excess hydrogen is a necessity to prevent poisoning of the Pt-anode by CO in PEMFCs (Polymer Electrolyte Membrane Fuel Cell). A highly active catalyst, 5 wt% Cu-CeO2 showed 100 % CO conversion at 65 degrees C without any undesirable oxidation of H-2. The catalyst showed no deactivation even after 100 h on stream, making it viable for practical fuel cell application. Operando EPR in the PROX reaction condition revealed highly dispersed mixed valent cations with oxygen vacancies, responsible for the low-temperature PROX activity. At the active site, both Cu and Ce ions were shown to reversibly change their valence states to facilitate the abstraction of bridging lattice oxygen for CO oxidation to CO2. This surface oxygen mediated CO oxidation was found to be much faster than that of H-2 to H2O, which could explain the complete selectivity of oxygen for CO2 formation.10aCuOx-CeO210ainterface10aOxygen vacancy10aPROX10aSynergistic1 aAdak, Shubhadeep1 aRabeah, Jabor1 aRanjan, Ravi1 aKhan, Tuhin, Suvra1 aPoddar, Mukesh, Kumar1 aGupta, Rishi, Kumar1 aSasaki, Takehiko1 aKumar, Sagar1 aBordoloi, Ankur1 aGopinath, Chinnakonda, S.1 aBruckner, Angelika1 aBal, Rajaram  uhttp://library.ncl.res.in/content/situ-experimental-and-computational-approach-investigate-nature-active-site-low-temperature03177nas a2200217   4500008004100000022001400041245013800055210006900193260000900262300001600271490000700287520239300294100002402687700002402711700001902735700002302754700001602777700001802793700002402811856012402835       2022                        eng d  a2040-336400aUnravelling faradaic electrochemical efficiencies over Fe/Co spinel metal oxides using surface spectroscopy and microscopy techniques0 aUnravelling faradaic electrochemical efficiencies over FeCo spin  cNOV   a15928-159410 v143 a<p>
	Cobalt and iron metal-based oxide catalysts play a significant role in energy devices. To unravel some interesting parameters, we have synthesized metal oxides of cobalt and iron (i.e. Fe2O3, Co3O4, Co2FeO4 and CoFe2O4), and measured the effect of the valence band structure, morphology, size and defects in the nanoparticles towards the electrocatalytic hydrogen evolution reaction (HER), the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). The compositional variations in the cobalt and iron precursors significantly alter the particle size from 60 to &lt;10 nm and simultaneously the shape of the particles (cubic and spherical). The Tauc plot obtained from the solution phase ultraviolet (UV) spectra of the nanoparticles showed band gaps of 2.2, 2.3, 2.5 and 2.8 eV for Fe2O3, Co3O4, Co2FeO4 and CoFe2O4, respectively. Further, the valence band structure and work function analysis using ultraviolet photoelectron spectroscopy (UPS) and core level X-ray photoelectron spectroscopy (XPS) analyses provided better structural insight into metal oxide catalysts. In the Co3O4 system, the valence band structure favors the HER and Fe2O3 favors the OER. The composites Co2FeO4 and CoFe2O4 show a significant change in their core level (O 1s, Co 2p and Fe 2p spectra) and valence band structure. Co3O4 shows an overpotential of 370 mV against 416 mV for Fe2O3 at a current density of 2 mA cm(-2) for the HER. Similarly, Fe2O3 shows an overpotential of 410 mV against the 435 mV for Co3O4 at a current density of 10 mA cm(-2) for the OER. However, for the ORR, Co3O4 shows 70 mV improvement in the half-wave potential against Fe2O3. The composites (Co2FeO4 and CoFe2O4) display better performance compared to their respective parent oxide systems (i.e., Co3O4 and Fe2O3, respectively) in terms of the ORR half-wave potential, which can be attributed to the presence of the oxygen vacancies over the surface in these systems. This was further corroborated in density functional theory (DFT) simulations, wherein the oxygen vacancy formation on the surface of CoFe2O4(001) was calculated to be significantly lower (similar to 50 kJ mol(-1)) compared to Co3O4 (001). The band diagram of the nanoparticles constructed from the various spectroscopic measurements with work function and band gap provides in-depth understanding of the electrocatalytic process.</p>
1 aKashyap, Varchaswal1 aPandikassala, Ajmal1 aSingla, Gourav1 aKhan, Tuhin, Suvra1 aHaider, Ali1 aVinod, C., P.1 aKurungot, Sreekumar  uhttp://library.ncl.res.in/content/unravelling-faradaic-electrochemical-efficiencies-over-feco-spinel-metal-oxides-using