@article {560,
	title = {Insertion and removal of protons in single-crystal orthorhombic molybdenum trioxide under H2S/H-2 and O-2/N-2},
	journal = {Chemistry of Materials},
	volume = {14},
	number = {4},
	year = {2002},
	note = {ISI Document Delivery No.: 542DRTimes Cited: 13Cited Reference Count: 49},
	month = {Apr},
	pages = {1788-1796},
	type = {Article},
	abstract = {Using AFM/XRD/XPS methods, in this paper, we investigate protonation and deprotonation processes in single-crystal samples of orthorhombic molybdenum trioxide (alpha-MoO3). At low temperatures, a small part of alpha-MoO3 is changed to needlelike HxMoO3 (x approximate to 0.33) along <203> directions in a H2S/H-2 gas stream. When these elongated crystallites assemble into a maze structure, the growth of HxMoO3 is gradually ceased due to closing entrance for hydrogen. At higher temperatures, the needlelike HxMoO3 crystallites turn to a growth perpendicular to <203>, which leads to the formation of HxMoO3 blocks. It is observed that the basal plane of alpha-MoO3 is severely buckled upon the protonation. Surface sulfidation is also observed. The formed HxMoO3 or surface MOS2, however, can be readily converted back to their original-phase alpha-MoO3 in air at 350-400 degreesC. This oxidation process gives rise to a flattened (010) topography (i.e., debuckling) on which shallowly divided alpha-MoO3 surface blocks bounded with {101} planes are formed. When an alpha-MoO3 (010) plane embedded with nanocrystallites is used to create surface stress or nucleation sites, the insertion mode of hydrogen along <001> is further reconfirmed in this work. A correlation of surface/bulk phases upon various chemical reactions is addressed, and a model to summarize these changes is also proposed.},
	keywords = {BRONZES, DECOMPOSITION, GROWTH, HXMOO3, HYDROGEN, MOO3, NUCLEAR-MAGNETIC-RESONANCE, RAY PHOTOELECTRON-SPECTROSCOPY, SILICA SUPPORTS, THIN-FILMS, XPS},
	isbn = {0897-4756},
	url = {<Go to ISI>://000175028700050},
	author = {Zeng, H. C. and Xie, F. and Wong, K. C. and Mitchell, K. A. R.}
}
@article {4331,
	title = {X-ray photoelectron spectroscopy studies of the reduction of MoO3 thin films by NH3},
	journal = {Applied Surface Science},
	volume = {136},
	number = {1-2},
	year = {1998},
	note = {ISI Document Delivery No.: 133ZGTimes Cited: 7Cited Reference Count: 33},
	month = {Oct},
	pages = {147-158},
	type = {Article},
	abstract = {X-ray photoelectron spectroscopy (XPS) has been used to gain insight into surface reaction pathways associated with the nitridation by NH3 of MoO3 thin films grown on metallic substrates. The samples formed can be seen as model hydrodenitrogenation (HDN) catalysts, but the more-controlled surface morphology allows spectral features to be studied in the absence of charging effects that can interfere with such measurements on high-area samples. Observed core level and valence spectra are consistent with the MoO3 being reduced, but the degree of reduction depends on the reaction temperature. Heating to 350 degrees C indicates some conversion to Mo(+5) and {\textquoteright}O-rich{\textquoteright} Mo(+4) components, while heating to 450 degrees C and to 700 degrees C give respectively a {\textquoteright}N-rich{\textquoteright} Mo(+4) form and a Mo(+3) oxynitride as the dominant components. It is concluded that the nitridation of MoO3 by NH3 involves initial hydrogenation, with subsequent elimination of water, and the effective replacement of O by N as the reduction continues. Surface compositions determined here during the nitridation process contrast with conclusions reached previously for the evolution of bulk phases as deduced by X-ray diffraction. (C) 1998 Elsevier Science B.V. All rights reserved.},
	keywords = {ADSORPTION, ammonia, Auger, CATALYSTS, DECOMPOSITION, HYDRODENITROGENATION, MOLYBDENUM NITRIDES, MOO3, NH3, REDUCTION, SURFACE-AREA, X-ray photoelectron spectroscopy, XPS},
	isbn = {0169-4332},
	url = {<Go to ISI>://000076717000022},
	author = {Leung, Y. L. and Wong, P. C. and Mitchell, K. A. R. and Smith, K. J.}
}
