Elevated electrocatalytic performance of A-site non-stoichiometric LaxNiO3 perovskites towards methanol oxidation reaction in NaOH solution

• Published in: Journal of solid state electrochemistry Vol. 27; no. 2; pp. 479 - 487
• Main Authors: Chen, Nian-Hua, Song, Tian-Yuan, Li, You-Fen, Zhang, Shuo, Yang, Ru
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-02-2023; Springer Nature B.V
• Subjects: Adsorption; Analytical Chemistry; Catalysts; Characterization and Evaluation of Materials; Chemical synthesis; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Density functional theory; Electrochemical oxidation; Electrochemistry; Energy bands; Energy Storage; Fuel cells; Methanol; Original Paper; Oxidation; Perovskites; Physical Chemistry; Stoichiometry; Non-stoichiometric; Nickel-based perovskite; Fuel cells; Catalyst; Methanol
• ISSN: 1432-8488; 1433-0768
• DOI: 10.1007/s10008-022-05341-5

Perovskite with the general formula ABO
3
has received great interest in the application of fuel cells. The catalytic performances of perovskite can be significantly influenced by regulating the A-site non-stoichiometric in direct methanol oxidation fuel cells. Herein, an A-site, non-stoichiometric nickel-based perovskite La
x
NiO
3
was synthesized and introduced as a catalyst for the electrochemical oxidation of methanol in fuel cells. Results show that La
0.95
NiO
3
exhibits a better onset potential of approximately 0.369 V. The current density is obtained with 52 mA/cm
2
at 0.6 V, which is 1.85 times higher than that of the standard perovskite LaNiO
3
. The catalytically active area of the catalyst was found to be strongly related to its La concentration. A high active area of 112.98 cm
2
for A-site-deficient La
0.95
NiO
3
was demonstrated at different sweep rates (10–100 mV/s). The density functional theory was employed to analyze the energy band structures, D-band centers, and methanol adsorption energy of a standard perovskite and the A-site-deficient perovskite. The Fermi level of the A-site-deficient perovskite La
0.95
NiO
3
catalyst spans more energy bands. Furthermore, catalyst La
0.95
NiO
3
has a higher D-band center (− 1.78 eV) and adsorption energy (− 1.21 eV), suggesting the A-site deficiency can produce the desired methanol oxidation reaction (MOR) catalyst activity.