Effect of oxide supports on palladium based catalysts for NO reduction by H2-SCR

• Published in: Catalysis today 2021-09, Vol.375, p.591-600
• Main Authors: Patel, Vivek Kumar, Sharma, Sweta
• Format: Article
• Language: English
• Subjects: Activity; Catalysis; Conversion; Reduction
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2020.04.006

[Display omitted] •Automotive catalysts supports prepared by co-precipitation method followed by metal impregnation technique.•Catalysts for the selective catalytic reduction of No with hydrogen.•Pd/ZrO2-CeO2 mixed oxide support shows more activity toward NO reduction.•Highly dispersed Pd active metal over ZrO2-CeO2 support with large extent of Ce3+ and adsorbed oxygen contents.•A positive catalyst for NO abatement in diesel engine exhaust. The present work shows the synthesis of various mixed oxide catalysts prepared by co-precipitation followed by impregnation of palladium metal. The catalysts are denoted as Pd/MgO-CeO2, Pd/ZrO2-CeO2, Pd/Al2O3-CeO2, and Pd/TiO2-CeO2 and examined for selective catalytic reduction (SCR) of NO with H2 in the presence of excess oxygen (6% O2). The properties of catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), BET, transmission electron microscopy (TEM), H2-temperature-programmed reduction (H2-TPR), and Raman spectroscopy. The synthesized catalysts exhibit notable NO reduction potential at 175 ℃ and in a wide temperature range from 100 to 400 ℃. Compared to bare CeO2 support, the Pd/ZrO2-CeO2 catalyst greatly enhances the SCR activity with a wide temperature range (100–400 ℃). The experimental results showed that the Pd/ZrO2-CeO2 catalyst had the best catalytic activity with 92 % NO reduction and a wide temperature reduction window (150–400 ℃) at the gas hour space velocity (GHSV) of 20,000 h−1.