Design a promising non-precious electro-catalyst for oxygen reduction reaction in fuel cells. (22nd February 2023)

• Record Type: Journal Article
• Authors: Sivaraman, R.; Opulencia, Maria Jade Catalan; Majdi, Ali; Patra, Indrajit; Kadhem Abid, Mohammed; Hammid, Ali Thaeer; Derakhshandeh, Maryam
• Is Part Of: International journal of hydrogen energy. Volume 48:Number 16(2023)
• Page Start: 6308
• Page End: 6316
• Publication Date: 2023-02-22
• Subjects: Oxygen reduction reaction -- Potential reaction -- Thermodynamics -- Pathway's -- Fuel cells; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.04.241
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: We utilized quantum-chemical computations for computing the thermodynamic variations in the Gibbs free energy of the potential reaction steps in the oxygen reduction reaction (ORR) of the nickel- and nitrogen-doped graphene (NiN3 -Gr) catalyst's active center. We observed the consistency of the energies of adsorption for all O-containing intermediates. The great thermodynamic driving forces (or motives) for reducing OOH into 2OH∗ or O∗ and the minor motives for generating H2 O2 show the advantageousness of following a 4-electron pathway compared to a 2-electron one. This reaction's rate-determining step has 0.94 eV energy barrier that is associated with the first H2 O molecule formation. According to the thermodynamics results, at lower than 0.51 V electrode potential by the 4e − pathway, the elementary steps of ORR are downhill. The last step, which is the OH reduction into H2 O with the largest value of ΔG, acts as the 4e − pathway's thermodynamic RDS. Experimental scientists can use the theoretical results achieved in the current study in order to synthesize and select appropriate combinations of NiN3 -Gr for applications in fuel cells. Highlights: The catalytic activity of a series of N and Fe-doped GDY has been theoretically explored in the ORR at the DFT level. O2 molecule can be directly dissociated on the N2 -doped Fe-GDY. It is reacting more favorable for the ER mechanism of OH∗ to convert into H2 O. The ORR reaction was found to be thermodynamically favorable in the N2 -doped Fe-GDY.