01625nas a2200157   4500008004100000022001400041245012600055210006900181260007100250300001400321490000700335520095400342100001501296700003001311856012601341       2014                        eng d  a0003-270000aUV photoelectron spectroscopy at near ambient pressures: mapping valence band electronic structure changes from Cu to CuO0 aUV photoelectron spectroscopy at near ambient pressures mapping   a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAPR  a3683-36870 v863 a<p>Valence band (VB) changes and hence electronic structure evolution was directly observed with low kinetic energy (KE) electrons at near ambient pressure (NAP) conditions with He I photon source in a custom built laboratory ambient pressure photoelectron spectrometer (Lab-APPES). Polycrystalline Cu surfaces were gradually oxidized in O-2 to Cu2O, to a mixture of Cu2O + CuO, and finally to CuO between 300 and 625 K and at NAP. Typical VB features for Cu, Cu2O, and CuO were observed, and the results corroborate well with core level and Auger spectral changes. High mean free path associated with low KE electrons, very low or no inelastic scattering, and effective pumping and the design of electrostatic lens regime help to minimize the electron attenuation at NAP conditions. The present results extend the capabilities of the APPES tool to explore the in situ evolution of electronic structure of materials at NAP and high temperatures.</p>1 aRoy, Kanak1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/uv-photoelectron-spectroscopy-near-ambient-pressures-mapping-valence-band-electronic-002423nas a2200217   4500008004100000022001400041245011600055210006900171260000800240300001400248490000600262520161300268100002801881700002601909700002801935700002101963700002701984700003402011700003002045856013002075       2025                        eng d  a2398-490200aUtilizing nature's endowment: artificial leaf concept for methane activation to C-C coupled ethanol or ethylene0 aUtilizing natures endowment artificial leaf concept for methane   cDEC  a6798-68100 v93 a<p>
	Methane activation (MA) to platform chemicals under ambient conditions still remains an open challenge to be fully realised. The present work shows the fabrication of CeVO4 quantum dots (CV-QDs) by a bottom-up approach; they are assembled from Ce3+ and metavanadate ions, and structurally and electronically integrated into the micro-/meso-pores of TiO2 (CV-QD-TiO2 (CVT)), demonstrating the conversion of MA to ethanol/ethylene by visible light-driven photocatalysis. CV-QDs in confined pores modify the quantum confinement effects and are characterized by physicochemical methods. The current synthetic strategy is potentially scalable and results in sub-quadrillion heterojunctions in a 1 mg CVT photoanode spread over 1 cm2. MA with CVT under one-sun conditions demonstrates similar to 100% selectivity to ethanol, yielding 4.36 mu mol h-1 cm-2, with a solar-to-fuel efficiency (STFE) of 0.56. Further, by employing a co-catalyst, significant STFE (5.08) and yield (39.5 mu mol h-1 cm-2) are achieved selectively towards ethylene. A deliberate addition of methanol increases the rate of ethanol production by 17.2 times, indicating that the methyl-methoxy interaction is the origin of C-C coupling. Weight is normalized to a gram of CV-QDs in a large area CVT photoanode to yield 109 mmol h-1 gCV-QD-1 of ethanol and 988 mmol h-1 gCV-QD-1 of ethylene. Enhanced activity and selectivity towards the C2-product is attributed to band-edge modulation and trillions of heterojunctions, which in turn facilitate charge separation and charge transfer for effective charge utilisation at redox sites.</p>
1 aKanungo, Subhashree, S.1 aMishra, Abhaya, Kumar1 aAvani, Mangaladasan, J.1 aBajpai, Himanshu1 aSalgaonkar, Kranti, N.1 aJavaregowda, Bharathkumar, H.1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/utilizing-natures-endowment-artificial-leaf-concept-methane-activation-c-c-coupled-ethanol