Issue 15, 2020

High pressure ammonia decomposition on Ru–K/CaO catalysts

Abstract

Potassium-promoted ruthenium supported on CaO is a very efficient catalyst for ammonia decomposition, surpassing the performance of other Ru-supported solids. At an optimum Ru loading of 3% wt, catalysts with a K/Ru atomic ratio of 0.9 showed the best catalytic performance under a wide range of operating conditions, P = 1–40 bar, T = 250–550 °C and WHSV = 9000–30 000 mL g−1 h−1. Although NH3 conversion levels decrease considerably upon increasing the reaction pressure (X550 °C, 40 bar = 0.8), high pressure ammonia decomposition offers the possibility of COx-free compressed hydrogen and hydrogen productivities and TOFs 40 times bigger than when applying atmospheric pressure. Extensive characterization by CO chemisorption and HR-TEM demonstrates that potassium promotion increases metal dispersion by decreasing the Ru particle size. Electronic effects derived from the close proximity between K and Ru result in a decrease in the reaction apparent activation energy, as shown by a detailed kinetic analysis.

Graphical abstract: High pressure ammonia decomposition on Ru–K/CaO catalysts

Supplementary files

Article information

Article type
Paper
Submitted
05 Apr 2020
Accepted
26 Jun 2020
First published
29 Jun 2020
This article is Open Access
Creative Commons BY license

Catal. Sci. Technol., 2020,10, 5027-5035

High pressure ammonia decomposition on Ru–K/CaO catalysts

S. Sayas, N. Morlanés, S. P. Katikaneni, A. Harale, B. Solami and J. Gascon, Catal. Sci. Technol., 2020, 10, 5027 DOI: 10.1039/D0CY00686F

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