Premium
Perovskites as Precursors for Ni/La 2 O 3 Catalysts in the Dry Reforming of Methane: Synthesis by Constant pH Co‐Precipitation, Reduction Mechanism and Effect of Ru‐Doping
Author(s) -
Kühl Stefanie,
Düdder Hendrik,
Girgsdies Frank,
Kähler Kevin,
Muhler Martin,
Behrens Malte
Publication year - 2017
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201700141
Subject(s) - catalysis , calcination , non blocking i/o , lanio , perovskite (structure) , inorganic chemistry , chemistry , decomposition , metal , precipitation , syngas , materials science , crystallography , organic chemistry , physics , optoelectronics , meteorology , dielectric , ferroelectricity
LaNiO 3 perovskite is an interesting precursor for Ni/La 2 O 3 catalysts for the dry reforming of methane at high temperatures. Precursors have been synthesized by co‐precipitation without, with 2.5 at %, and with 5 at % Ru doping. The presence of Ru leads to a stabilization of the perovskite structure and hinders the decomposition into NiO and Ruddlesden‐Popper mixed oxides La n +1 Ni n O 3 n +1 , which was observed for the Ru‐free sample upon calcination at 1000 °C ( n = 3). Upon reduction in hydrogen, a mechanism involving at least two steps was observed and the first major step was identified as the partial reduction of the precursor leading to a LaNiO 2.5 ‐like intermediate. The second major step is the reduction to Ni metal supported on La 2 O 3 independent of the Ru content of the catalyst. In the presence of Ru, indications for Ni‐Ru alloy formation and for a higher dispersion of the metallic phase were found. The catalytic activity in DRM of the catalyst containing 2.5 % Ru was superior to the catalysts with more or without Ru. Furthermore, the propensity of coke formation was reduced by the presence of Ru.