Selective Catalytic Reduction with Hydrogen for Exhaust gas after-treatment of Hydrogen Combustion Engines

• Published in: Topics in catalysis Vol. 66; no. 13-14; pp. 973 - 984
• Main Authors: Borchers, Michael, Lott, Patrick, Deutschmann, Olaf
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2023; Springer Nature B.V
• Subjects: Aluminum oxide; Ammonia; Catalysis; Catalysts; Catalytic converters; Characterization and Evaluation of Materials; Chemical reduction; Chemistry; Chemistry and Materials Science; Conversion; Engines; Exhaust gases; Formulations; Gas mixtures; Gases; Hydrogen; Hydrogen combustion; Industrial Chemistry/Chemical Engineering; Nitrogen oxides; Original Paper; Palladium; Pharmacy; Physical Chemistry; Selective catalytic reduction; Titanium dioxide; X ray powder diffraction; Zeolites; NOx Abatement; SCR; Selective Catalytic Reduction with Hydrogen (H; Zeolites; Palladium Catalyst; Hydrogen Internal Combustion Engine
• ISSN: 1022-5528; 1572-9028
• DOI: 10.1007/s11244-022-01723-1

In this work, two palladium-based catalysts with either ZSM-5 or Zeolite Y as support material are tested for their performance in selective catalytic reduction of NOx with hydrogen (H 2 -SCR). The ligh-toff measurements in synthetic exhaust gas mixtures typical for hydrogen combustion engines are supplemented by detailed catalyst characterization comprising N 2 physisorption, X-ray powder diffraction (XRD), hydrogen temperature programmed reduction (H 2 -TPR) and ammonia temperature programmed desorption (NH 3 -TPD). Introducing 10% or 20% TiO 2 into the catalyst formulations reduced the surface area and the number of acidic sites for both catalysts, however, more severely for the Zeolite Y-supported catalysts. The higher reducibility of the Pd particles that was uncovered by H 2 -TPR resulted in an improved catalytic performance during the light-off measurements and substantially boosted NO conversion. Upon exposition to humid exhaust gas, the ZSM-5-supported catalysts showed a significant drop in performance, whereas the Zeolite Y-supported catalyst kept the high levels of conversion while shifting the selectivity from N 2 O more toward NH 3 and N 2 . The 1%Pd/20%TiO 2 /HY catalyst subject to this work outperforms one of the most active and selective benchmark catalyst formulations, 1%Pd/5%V 2 O 5 /20%TiO 2 -Al 2 O 3 , making Zeolite Y a promising support material for H 2 -SCR catalyst formulations that allow efficient and selective NOx-removal from exhaust gases originating from hydrogen-fueled engines.