Elucidating the Role of Oxide–Oxide/Carbon Interfaces of CuO_x–CeO₂/C in Boosting Electrocatalytic Performance

Abstract

Herein, we report the synthesis and bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities of a CuO x −CeO 2 /C electrocatalyst (EC) with rich oxide−oxide and oxide−carbon interfaces. It not only demonstrates a smaller Tafel slope (65 mV dec −1 ) and higher limiting current density (−5.03 mA cm −2 ) but also exhibits an onset potential (−0.10 V vs Ag/AgCl) comparable to that of benchmark Pt/C. Besides undergoing the favorable direct four-electron ORR pathway, it unveils a loss of 23% of its initial current after 6 h of a stability test and a negative shift of 4 mV in the half-wave potential after the accelerated durability test compared to the corresponding current loss of 28% and negative shift of 20 mV for Pt/C. It also reveals remarkable OER activity in an alkaline medium with a low onset potential (0.20 V) and a smaller Tafel slope (177 mV dec −1 ). The bifunctional ORR/OER activity of CuO x −CeO 2 /C EC can be ascribed to the synergistic effects, its unique structure with enriched oxygen vacancies owing to the presence of Ce 4+ /Ce 3+ , robust oxide−oxide and oxide−carbon heterointerfaces, and homogeneous dispersion of oxides over the carbon bed, which facilitates faster electronic conduction.

A Review of Transition Metal Oxygen-Evolving Catalysts Decorated by Cerium-Based Materials: Current Status and Future Prospects

“…78 Through the similar process, Bharali and coworkers synthesized a nanostructured CuO x -CeO 2 /C electrocatalyst with abundant surface oxygen vacancies and distinguished oxide-oxide/carbon interfaces. 79 Worthy of note, Ni and coworkers developed a novel CeO 2 /LaFeO 3 hybrid via a facile chemical bath method.…”

Nonprecious Hybrid Metal Oxide for Bifunctional Oxygen Electrodes: Endorsing the Role of Interfaces in Electrocatalytic Enhancement

“…Our previous work also revealed that the CuO x −CeO 2 /C EC exhibited high performance toward the ORR and OER compared to their single MOs. 24 Oxygen electrocatalysis, nowadays, is highly prioritized due to its significant role in the productivity of alternative energy devices, such as metal−air batteries, 20 fuel cells (FCs), 25 and electrolyzers, 26 which delivers power at decent rates. The two dominant electrode reactions occurring in such energy devices are the ORR and OER.…”

Oxygen Reduction Reaction Catalysed by Supported Nanoparticles: Advancements and Challenges

“…The electrocatalytic ORR activity is studied via cyclic voltammetry (CV) and linear sweep voltammetry (LSV) methods. [14,15] LSV is generally recorded by rotating disk electrode (RDE) and rotating ring disk electrode (RRDE). These rotation dependent techniques offer good control of the reaction hydrodynamics by creating a laminar flux of analyte toward and outward the rotating electrode surfaces.…”

“…The electrocatalytic ORR activity is studied via cyclic voltammetry (CV) and linear sweep voltammetry (LSV) methods [14,15] . LSV is generally recorded by rotating disk electrode (RDE) and rotating ring disk electrode (RRDE).…”