01619nas a2200217   4500008004100000022001400041245007500055210006900130260011000199300001600309490000600325520081000331100001801141700002201159700002001181700001801201700002701219700003001246700002001276856010501296       2016                        eng d  a2046-206900aSeeding of Au on CdSe/CdS nanoplates using Langmuir-Blodgett technique0 aSeeding of Au on CdSeCdS nanoplates using LangmuirBlodgett techn  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJAN  a14658-146650 v63 a<p>Oleyl amine capped CdSe/CdS nanoplates were synthesized by hot injection technique which formed a stable monolayer over both a water subphase and an aqueous HAuCl4 subphase using a Langmuir-Blodgett trough. Au islands were generated at the edge as well as on one specific surface of the flat nanoplates by exploiting the reducing capacity of oleyl amine to form Au nanoseeds from AuCl4- ions. The initial Au nanoseeds changed to a shell surrounding these nanoplates on prolonged exposure to the subphase containing the Au precursor. Monolayer of the hybrid structures was deposited onto suitable substrates for characterization by a number of different techniques and to study the photocatalytic activity. The same substrate with the monolayers could be re-used in several cycles of photocatalysis.</p>1 aDas, Subhasis1 aSatpati, Biswarup1 aChauhan, Himani1 aDeka, Sasanka1 aGhosalya, Manoj, Kumar1 aGopinath, Chinnakonda, S.1 aBala, Tanushree  uhttps://library.ncl.res.in/content/seeding-au-cdsecds-nanoplates-using-langmuir-blodgett-technique-002626nas a2200181   4500008004100000022001400041245012400055210006900179260000900248300001400257490000800271520193900279100002702218700001602245700002902261700003002290856012402320       2018                        eng d  a1932-744700aSilicon oxidation by NAPPES: From dangling bonds to oxygen islands to 2D SiOx layer to the onset of bulk SiO2 formation0 aSilicon oxidation by NAPPES From dangling bonds to oxygen island  cMAR   a4331-43380 v1223 a<p>Valence band and core level photoelectron spectral measurements at near-ambient pressures (NAP; up to 0.5 mbar) were made in the presence of molecular oxygen to explore the various oxidation stages of silicon surfaces. Dangling bonds feature observed on clean Si-surfaces in the valence band at ultrahigh vacuum decreases dramatically due to oxygen adsorption between ambient temperature and up to 400 K at 0.1 mbar of O-2 pressure. The adsorption of oxygen on dangling bonds appears to be localized as islands; this reflects in the surface heterogeneous character and also responsible for the broadening in the oxygen gas phase vibrational features. This is further supported by an increase in the work function and can be correlated to the presence of Hofer (molecular) precursor. When the temperature was increased to 500 K, molecular precursor species dissociates to form Si-=-0 species. This is fully supported by the change in the Si work function as well as from the observation of oxidized Si species from Si 2p core level spectra. At &gt;= 600 K, the Si-=-0 species dissociates to form a uniform 2D oxide layer on the silicon surface, which is characterized by the reappearance of sharp vibration features for gas-phase O-2 molecules. This layer is also quite stable up to 800 K and without any further oxidation in the bulk. On increasing the temperature to 850 K at 0.2 mbar oxygen pressure, bulk Si oxidation begins and the work function increases drastically by 1 eV. An angle-dependent Si 2p spectra recorded map out the presence of elemental Si to Si4+ from bulk to the surface, respectively. A simple model is proposed to show the various stage of silicon oxidation. A continuous change in the work function and electronic states observed due to gas-lattice (O-2-Si) interaction indicates the implications for surface-dependent phenomena, such as heterogeneous catalysis, electrochemistry, 2D layered materials.</p>1 aGhosalya, Manoj, Kumar1 aJain, Ruchi1 aReddy, Kasala, Prabhakar1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/silicon-oxidation-nappes-dangling-bonds-oxygen-islands-2d-siox-layer-onset-bulk-sio202198nas 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-spectroscopy