APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014;
Denver, Colorado
Session T2: Surfaces, Nanoparticles, and Materials
11:15 AM–2:15 PM,
Thursday, March 6, 2014
Room: 102
Sponsoring
Unit:
DCP
Chair: Gilbert Nathanson, University of Wisconsin-Madison
Abstract ID: BAPS.2014.MAR.T2.12
Abstract: T2.00012 : Formation, stability, and reactivity studies of neutral iron sulfide clusters
1:27 PM–1:39 PM
Preview Abstract
Abstract
Authors:
Shi Yin
(Chemistry Department, Colorado State University)
Zhechen Wang
(Chemistry Department, Colorado State University)
Elliot Bernstein
(Chemistry Department, Colorado State University)
Different methods are used to generate neutral iron sulfide clusters to
study their formation, stability, and reactivity, employing a time of flight
mass spectrometer (TOFMS) with VUV (118 nm) radiation single photon
ionization (SPI). Neutral Fe$_{m}$S$_{n}$ ($m \quad =$ 1-4, $n \quad =$1-6 ), and hydrogen
containing Fe$_{m}$S$_{n}$H$_{x}$ ($x$ \textgreater 0,$ n$ \textgreater $m)$ clusters
are generated by the reaction of seeded H$_{\mathrm{2}}$S in a helium
carrier gas with laser ablated iron metal within a supersonic nozzle. The
observed strong signal of association products
Fe$_{\mathrm{2}}$S$_{\mathrm{2}}$(SH)$_{\mathrm{0,1}}M$ ($M \quad =$ CO,
C$_{\mathrm{2}}$H$_{\mathrm{4}}$, C$_{\mathrm{3}}$H$_{\mathrm{6}})$ suggest
that the Fe$_{\mathrm{2}}$S$_{\mathrm{2}}$(SH)$_{\mathrm{0,1}}$ clusters
have the high activity for interactions with these small molecules. In order
to avoid the effect for reactivity from hydrogen containing clusters, pure
Fe$_{m}$S$_{n} $clusters are generated through laser ablation of a mixed
iron/sulfur target in the presence of a pure helium carrier gas. (FeS)$_{m}$
($m \quad =$ 1-4) is observed to be the most stable series. Reaction of CO and
H$_{\mathrm{2}}$ on neutral (FeS)$_{\mathrm{1,2}} $clusters is farther
investigated both experimentally and theoretically. A size dependent
reactivity of iron sulfide clusters \quad toward CO is characterized. The reaction
FeS $+$ CO $\to $ Fe $+$ OCS is found for the FeS cluster. Products
Fe$_{\mathrm{2}}$S$_{\mathrm{2}}^{\mathrm{13}}$COH$_{\mathrm{2}}$ and
Fe$_{\mathrm{2}}$S$_{\mathrm{2}}^{\mathrm{13}}$COH$_{\mathrm{4}}$ are
identified for reactions of $^{\mathrm{13}}$CO and H$_{\mathrm{2}}$ on
Fe$_{\mathrm{2}}$S$_{\mathrm{2}}$ clusters: this suggests that the
Fe$_{\mathrm{2}}$S$_{\mathrm{2}}$ cluster has a high catalytic activity for
hydrogenation reactions of CO to form formaldehyde and methanol. DFT
calculations are performed to explore the potential energy surfaces for the
two reactions: Fe$_{\mathrm{2}}$S$_{\mathrm{2}} \quad +$ CO $+$
2H$_{\mathrm{2}} \quad \to $ Fe$_{\mathrm{2}}$S$_{\mathrm{2}} \quad +$
CH$_{\mathrm{3}}$OH; and Fe$_{\mathrm{2}}$S$_{\mathrm{2}} \quad +$ CO $+$
H$_{\mathrm{2}} \quad \to $ Fe$_{\mathrm{2}}$S$_{\mathrm{2}} \quad +$
CH$_{\mathrm{2}}$O.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.T2.12