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Download fileTransition Metal-Free Alkyne Hydrogenation Catalysis with BaGa2, a Hydrogen Absorbing Layered Zintl Phase
journal contribution
posted on 11.12.2019, 18:51 authored by Kelsey
L. Hodge, Joshua E. GoldbergerInexpensive, transition metal-free intermetallic compounds
have
received almost no attention as heterogeneous catalysts. Here, we
show that BaGa2, a Zintl–Klemm compound composed
of honeycomb sheets of Ga– anions separated by Ba2+ cations and known to react with H2 under moderate
conditions to form a layered polyanionic hydride BaGa2H2, effectively catalyzes the hydrogenation of phenylacetylene
into styrene and ethylbenzene under modest conditions (1–50
bar H2, 40–100 °C). Remarkably, the catalytic
activity of BaGa2 (surface specific activities up to 8390
h–1) is on the same order of magnitude as commercial
Pd-based catalysts. In contrast, BaGa2H2 shows
negligible catalytic activity, thereby indicating that the unsaturated
Ga– framework is necessary for phenylacetylene and
styrene adsorption. These findings open up future explorations of
utilizing and optimizing the long-term stability of transition metal-free
intermetallic hydrogen absorbing compounds for hydrogen-based catalysis.