Ammonia as a carrier for hydrogen production by using lanthanum based perovskites. (15th October 2021)

• Record Type: Journal Article
• Authors: Pinzón, M.; Sánchez-Sánchez, A.; Sánchez, P.; de la Osa, A.R.; Romero, A.
• Is Part Of: Energy conversion and management. Volume 246(2021)
• Publication Date: 2021-10-15
• Subjects: Ammonia decomposition -- Hydrogen production -- LaNiO3 -- LaCoO3 -- Perovskite-derived catalyst -- Self-combustion; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2021.114681
• Languages: English
• ISSNs: 0196-8904

Abstract

Graphical abstract: Highlights: Lanthanum perovskites are promising catalyst precursors for H2 production from NH3. Catalytic activity is influenced by the synthesis conditions of the perovskites. Proper qualities can be obtained with citric acid/metal nitrates molar ratio of 1. Calcination at 650 °C (Ni) and a molar ratio of 1 achieve a 99% NH3 conversion. Selected catalysts from perovskites show excellent stability after 24 h of reaction. Abstract: LaNiO3 and LaCoO3 perovskites synthesized by self-combustion were characterised and studied in the ammonia decomposition reaction for obtaining hydrogen. Both the fuel to metal nitrates molar ratio and calcination temperature were found to be crucial to synthesize perovskites by self-combustion. Moreover, generating non-precursor species during synthesis and small metal size were two factors which significantly influenced catalytic activity. Hence, with a citric acid to metal nitrates molar ratio equal to one a LaNiO3 perovskite was obtained with suitable physicochemical properties (specific surface area, lower impurities, and basicity). In addition, a lower calcination temperature (650 °C) resulted in small and well-dispersed Ni 0 crystallite size after reduction, which in turn, promoted the catalytic transformation of ammonia into hydrogen. For cobalt perovskites, calcination temperature below 900 °C did not have a significant influence on the size of the metallic cobalt crystallite size. The nickel and cobalt perovskite-derived catalysts, calcined at 650 °C and 750 °C, respectively, yielded excellent H2 production from ammonia decomposition. In particular, at 450 °C almost 100% of the ammonia was converted over the LaNiO3 under study. Furthermore, these materials displayed admirable performance and stability after one day of reaction.