@article {44536,
	title = {Subtle interaction between Ag and O 2 : a near ambient pressure UV photoelectron spectroscopy (NAP-UPS) investigations},
	journal = {Journal of Chemical Sciences},
	volume = {130},
	year = {2018},
	month = {MAR},
	pages = {30},
	type = {Journal Article},
	abstract = {The 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{\textendash}390 K, where mainly dissociative chemisorption of
O2 happens, (b) 390{\textendash}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{\textendash}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{\textendash}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.},
	keywords = {Electronic Structure, epoxidation, heterogeneous catalysis, Surface Science},
	issn = {9743626},
	doi = {10.1007/s12039-018-1434-3},
	author = {Ghosalya, Manoj Kumar},
	editor = {Reddy, Kasala Prabhakar}
}
@article {46813,
	title = {Electronic structure evolution of Pd@Co nanocatalysts under oxidation and reduction conditions and preferential CO oxidation},
	journal = {ChemCatChem},
	volume = {12},
	year = {2020},
	month = {AUG },
	pages = {4176-4184},
	type = {Article},
	abstract = {<p>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.</p>
},
	keywords = {Core-Shell morphology, Electronic Structure, heterogeneous catalysis, interface, XPS},
	issn = {1867-3880},
	doi = {10.1002/cctc.202000644, Early Access Date = JUN 2020},
	author = {Jain, Ruchi and Gopinath, Chinnakonda S.}
}
