Kinetic and mechanistic analysis of NH3decomposition on Ru(0001), Ru(111) and Ir(111) surfaces
Open Access
- 10 February 2021
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Nanoscale Advances
- Vol. 3 (6), 1624-1632
- https://doi.org/10.1039/d1na00015b
Abstract
We investigated the catalytic NH3 decomposition on Ru and Ir metal surfaces using density functional theory. The reaction mechanisms were unraveled on both metals, considering that, on the nano-scale, Ru particles may also present an fcc structure, hence, leading to three energy profiles. We implemented thermodynamic and kinetic parameters obtained from DFT into microkinetic simulations. Batch reactor simulations suggest that hydrogen generation starts at 400 K, 425 K and 600 K on Ru(111), Ru(0001) and Ir(111) surfaces, respectively, in excellent agreement with experiments. During the reaction, the main surface species on Ru are NH, N and H, whereas on Ir(111), it is mainly NH. The rate-determining step for all surfaces is the formation of molecular nitrogen. We also performed temperature-programmed reaction simulations and inspected the desorption spectra of N2 and H2 as a function of temperature, which highlighted the importance of N coverage on the desorption rate.Keywords
Funding Information
- China Scholarship Council (201806370221)
- Engineering and Physical Sciences Research Council (EP/P005845/1, EP/L000202, EP/R029431, EP/P020194)
This publication has 71 references indexed in Scilit:
- Computational Investigation on Adsorption and Dissociation of the NH3 Molecule on the Fe(111) SurfaceThe Journal of Physical Chemistry C, 2010
- Crystallographic Properties of IridiumPlatinum Metals Review, 2010
- Characterization of Iridium Catalyst for Decomposition of Hydrazine Hydrate for Hydrogen GenerationCatalysis Letters, 2006
- Kinetic study of NH3 decomposition over Ni nanoparticles: The role of La promoter, structure sensitivity and compensation effectApplied Catalysis A: General, 2005
- Dynamics of ammonia decomposition on Ru(0001)The Journal of Chemical Physics, 2000
- From ultrasoft pseudopotentials to the projector augmented-wave methodPhysical Review B, 1999
- Improved tetrahedron method for Brillouin-zone integrationsPhysical Review B, 1994
- Steady-state isotopic transient-kinetic analysis of iron-catalyzed ammonia synthesisJournal of Catalysis, 1989
- Development of transition-state theoryThe Journal of Physical Chemistry, 1983
- The Activated Complex in Chemical ReactionsThe Journal of Chemical Physics, 1935