Efficient bifunctional cerium-zeolite electrocatalysts for oxygen evolution and oxygen reduction reactions in alkaline media

• Published in: Synthetic metals Vol. 292; p. 117231
• Main Authors: Milikić, Jadranka, Stojanović, Srna, Damjanović-Vasilić, Ljiljana, Vasilić, Rastko, Šljukić, Biljana
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2023
• Subjects: Bifunctional electrocatalysts; Cerium-zeolite; Oxygen evolution reaction; Oxygen reduction reaction; Cerium-zeolite; Oxygen evolution reaction; Oxygen reduction reaction; Bifunctional electrocatalysts
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2022.117231

Four cerium-zeolites were examined as low-cost bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in an alkaline solution. Cerium-exchanged zeolites, synthetic 13X and natural clinoptilolite were employed as prepared and calcined (cal). Four samples (Ce-13X cal, Ce-13X, Ce-Cli cal, and Ce-Cli) were characterized by X-ray powder diffraction analysis (XRPD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, fluorescence spectroscopy and Brunner-Emmet-Teller (BET) method. All four zeolites exhibited activity for the two studied reactions. Ce-13X cal gave the lowest onset potential accompanied by the highest OER current density. Furthermore, Ce-13X cal showed the most positive ORR onset potential value of 0.84 V and the most positive ORR half-wave potential of 0.75 V (ca. 50 mV more positive than value for the other three cerium-zeolite electrodes) accompanied by the lowest Tafel slope of 80 mV dec−1. Koutecky-Levich analysis indicated that ORR follows 2-electron pathway. Overall, Ce-13X cal showed the best OER/ORR performances in alkaline solution. [Display omitted] •Four cerium-zeolites showed OER/ORR activity in alkaline media.•Ce-13X cal gave the highest OER current density.•The lowest OER onset potential of 1.60 V was observed for Ce-13X cal•Ce-13X cal showed the most positive ORR onset potential value of 0.84 V.