Exhaust energy recovery via catalytic ammonia decomposition to hydrogen for low carbon clean vehicles

Sak Sittichompoo, Hadi Nozari, Martin Herreros, Nahil Serhan, Julio da Silva, Andrew York, Paul Millington, Athanasios Tsolakis

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)
361 Downloads (Pure)


The work presented here, demonstrates the on-board exhaust assisted catalytic ammonia (NH3) conversion to H 2-N 2 using either only exhaust heat (decomposition) or by direct reaction with part of the exhaust gas (reforming). The resultant H 2-N 2 gas mixture from the exhaust heat driven thermochemical energy recovery processes contains up to 15% more energy than the reactant NH 3 (i.e. for 1 kW of NH 3 used in the reaction up to 1.15 kW of H 2 is produced). Experimental studies using a rhodium-platinum (Rh-Pt) catalyst and equilibrium calculations in Chemkin using Konnov's 0.6 and Nozari's reduced mechanisms have revealed that complete NH 3 conversion occurs at typical gasoline direct injection (GDI) engine exhaust gas temperatures (450 °C–550 °C). By partially replacing gasoline in GDI engine with the resultant (H 2-N 2 products, up to 30% reduction in CO 2 and fuels consumption can be achieved. Additional benefits can be gained under real engine operation when the benefits of reduced pumping losses, due to intake dilution with H 2-N 2 gas, are also considered. Furthermore, the work demonstrates additional benefits in CO 2 life cycle for the NH 3 use as an energy carrier in transportation and broader combustion power generation systems.

Original languageEnglish
Article number119111
Early online date6 Sept 2020
Publication statusPublished - 1 Feb 2021


  • Ammonia decomposition
  • Energy recovery
  • Gasoline engine emission
  • Hydrogen production
  • Reforming catalyst

ASJC Scopus subject areas

  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Organic Chemistry


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