Self-combustion Ni and Co-based perovskites as catalyst precursors for ammonia decomposition. Effect of Ce and Mg doping. (1st September 2022)

• Record Type: Journal Article
• Authors: Pinzón, M.; Sánchez-Sánchez, A.; Romero, A.; de la Osa, A.R.; Sánchez, P.
• Is Part Of: Fuel. Volume 323(2022)
• Publication Date: 2022-09-01
• Subjects: Ammonia decomposition -- Hydrogen production -- Perovskites -- Nickel -- Ceria -- Magnesia; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2022.124384
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Mono and bimetallic perovskites are catalyst precursors for H2 production from NH3. Co content on bimetallic perovskites and the addition of two dopant were optimized. LaCo1-x Nix O3 lead higher Ni crystallite size than pure LaNiO3 decreasing activity. Ce and Mg dopants on LaNiO3 perovskites reduce Ni size and increase basicity. Mg dopant (0.9 mol/mol) leads 72% NH3 conversion at 350 °C with admirable stability. Abstract: LaCo1-x Nix O3 perovskites have been synthesized by self-combustion, characterized, and examined as catalyst precursors for the COx -free hydrogen production from catalytic ammonia decomposition at low temperatures. The influence of the cobalt content as well as the addition of two dopant in different amount was studied and optimized. Small Ni crystallite size and high total basic sites were found to remarkably enhance the catalytic activity. Moreover, bimetallic perovskites generated cobalt/nickel in higher size, higher impurities and lower active sites than pure nickel perovskite, which decreased the ammonia conversion. On the other hand, the addition of dopant in adequate amount over pure Ni perovskite (La0.1 A0.9 NiO3 ; A = Ce or Mg) generated catalyst with low nickel crystallite size and high basicity delivering superior catalytic performance. Catalysts were demonstrated to be stable for at least 40 h. In fact, 96 % and 98 % ammonia conversion were achieved at low temperature (400 °C), when La0.1 Ce0.9 NiO3 and La0.1 Mg0.9 NiO3 were employed, resulting from the synergic effect between La-Ce and Ni-Mg-La. Presenting the Mg-doped perovskite the highest catalytic activity at the mild temperature of 350 °C. This study provides new insight in designing diverse catalyst precursors to develop economic and efficient catalysts to achieve high ammonia conversion (high hydrogen production) at low temperature and enhance the ammonia perspective as hydrogen carrier toward the 'hydrogen economy'.