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Nitrogen Fixation with Water Vapor by Nonequilibrium Plasma: toward Sustainable Ammonia Production
journal contribution
posted on 2020-02-12, 18:09 authored by Yury Gorbanev, Elise Vervloessem, Anton Nikiforov, Annemie BogaertsAmmonia
is a crucial nutrient used for plant growth and as a building
block in the pharmaceutical and chemical industry, produced via nitrogen
fixation of the ubiquitous atmospheric N2. Current industrial
ammonia production relies heavily on fossil resources, but a lot of
work is put into developing nonfossil-based pathways. Among these
is the use of nonequilibrium plasma. In this work, we investigated
water vapor as a H source for nitrogen fixation into NH3 by nonequilibrium plasma. The highest selectivity toward NH3 was observed with low amounts of added H2O vapor,
but the highest production rate was reached at high H2O
vapor contents. We also studied the role of H2O vapor and
of the plasma-exposed liquid H2O in nitrogen fixation by
using isotopically labeled water to distinguish between these two
sources of H2O. We show that added H2O vapor,
and not liquid H2O, is the main source of H for NH3 generation. The studied catalyst- and H2-free
method offers excellent selectivity toward NH3 (up to 96%),
with energy consumption (ca. 95–118 MJ/mol) in the range of
many plasma-catalytic H2-utilizing processes.