Growth of polyoxomolybdate with a porous pyramidal structure on carbon xerogel nanodiamond as an efficient electro-catalyst for oxygen reduction reaction

Abeer Enaiet Allah; Mohamed M El-Deeb; Ahmed A Farghali; H El Moll; Abdalla Abdelwahab

doi:10.1039/d2ra07543a

Growth of polyoxomolybdate with a porous pyramidal structure on carbon xerogel nanodiamond as an efficient electro-catalyst for oxygen reduction reaction

RSC Adv. 2023 Mar 13;13(12):8090-8100. doi: 10.1039/d2ra07543a. eCollection 2023 Mar 8.

Authors

Abeer Enaiet Allah¹, Mohamed M El-Deeb², Ahmed A Farghali³, H El Moll⁴, Abdalla Abdelwahab^{3

5}

Affiliations

¹ Chemistry Department, Faculty of Science, Beni-Suef University Beni-Suef 62511 Egypt.
² Applied Electrochemistry Laboratory, Chemistry Department, Faculty of Science, Beni-Suef University 62511 Beni-Suef Egypt.
³ Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences, Beni-Suef University Beni-Suef 62511 Egypt aabdelwahab@psas.bsu.edu.eg.
⁴ Department of Chemistry, College of Science, University of Hail P.O. Box 2440 81451 Hail Kingdom of Saudi Arabia.
⁵ Faculty of Science, Galala University Sokhna Suez 43511 Egypt.

Abstract

The slow kinetics of the oxygen reduction reaction (ORR) limits the large-scale usage of the fuel cells. Thus, it is crucial to develop an efficient and stable electrocatalyst for the ORR. Herein, facile synthesis of three-dimensional nitrogen-doped carbon xerogel diamond nanoparticles, CDNPs support is reported. The as-prepared CDNPs support was functionalized with a Keggin-type polyoxomolybdate via the hydrothermal process (POM@CDNPs). As the characterization techniques revealed, this nanocomposite possesses a three-dimensional structure, high density of nitrogen doping, and well-dispersed porous pyramidal morphology of POM, making it a promising catalyst for ORR in alkaline medium. The POM@CDNPs nanocomposite exhibits an outstanding activity for ORR with a limiting current density that reaches -7.30 mA cm^-2 at 0.17 V vs. RHE. Moreover, a half-wave potential of 0.773 V is delivered with a stability of about 99.9% after the 100th repetitive cycle as this catalyst forces the ORR to the direct-four-electron pathway. This work spots the advantages of hybridizing the sp³ of the nanodiamond with the sp² of the carbon xerogels to increase the conductivity of the support material. In addition, the role of the porous pyramidal morphology of the POM on the activity of the nanocomposite was evaluated. This study suggests using advanced carbon-based electro-catalysts with outstanding activity and stability.