LOHC-bound hydrogen for catalytic NOx reduction from O2-rich exhaust gas

The present study demonstrates a novel method for the NOx reduction by H2 in lean exhaust gases using H2 released from a Liquid Organic Hydrogen Carrier (LOHC). The concept implies the simultaneous H2 production and H2-deNOx reaction, which both take place on the same catalyst. In a first approach, the catalyst was suspended in the LOHC, while the exhaust flowed through the slurry. The experiments performed with a O2-rich model exhaust and perhydro dibenzyltoluene as LOHC as well as Pd/C, Pt/C and Pt/Al2O3 catalysts evidenced the feasibility of this transfer hydrogenation. As a result, the Pd/C catalyst revealed best H2-deNOx performance providing NOx conversions up to 98% above 200 degrees C with almost selective N2 formation. The characterization of the catalysts by temperature-programmed desorption of CO suggested that the superiority of the Pd/C sample is associated with its pronounced number of active Pd sites. Furthermore, the investigations also showed some LOHC degradation during the exposure to the lean model exhaust yielding CO, CO2 and hydrocarbons. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Superscript/Subscript Available

Automated summary

This study demonstrates a novel method for NOx reduction in lean exhaust gases using hydrogen released from a Liquid Organic Hydrogen Carrier (LOHC). The experiments confirmed the feasibility of simultaneous H2 production and H2-deNOx reaction on the same catalyst, with Pd/C catalyst showing the best performance. The investigation also revealed some LOHC degradation during exposure to lean exhaust gases.