Ce–Metal–Organic Framework-Derived CeO[sub.2]–GO: An Efficient Electrocatalyst for Oxygen Evolution Reaction

• Published in: Inorganics Vol. 11; no. 4
• Main Authors: Nagajyothi, Patnamsetty Chidanandha, Pavani, Krishnapuram, Ramaraghavulu, Rajavaram, Shim, Jaesool
• Format: Journal Article
• Language: English
• Published: MDPI AG 01-04-2023
• Subjects: Analysis; Cerium; Chemical properties; Chemical reactions; Diffraction; Electron microscopy; Graphene; Mechanical properties; Methods; Organometallic compounds; Oxides; Photoelectron spectroscopy; Scanning microscopy; Structure; X-ray spectroscopy; X-rays; South Korea; India
• ISSN: 2304-6740
• DOI: 10.3390/inorganics11040161

The oxygen evolution reaction (OER) is a crucial half-reaction in water splitting. However, this reaction is kinetically sluggish owing to the four-electron (4 e[sup.−] ) transfer process. Therefore, the development of low-cost, stable, highly efficient, and earth-abundant electrocatalysts for the OER is highly desirable. Metal oxides derived from metal–organic frameworks (MOFs) are among the most efficient electrocatalysts for the OER. Herein, Ce–MOF-derived CeO[sub.2] /graphene oxide (GO) composites were successfully prepared using a facile method. The composites with 0, 25, 50, and 100 mg GO were named CeO[sub.2] , CeO[sub.2] –GO-1, CeO[sub.2] –GO-2, and CeO[sub.2] –GO-3, respectively. The physicochemical characteristics of the electrocatalysts were assessed using several analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) analysis. The TEM results revealed that the CeO[sub.2] had a sheet-like morphology and that a GO layer was noticeable in the synthesized CeO[sub.2] –GO-3 composite. The characterization results confirmed the formation of impurity-free CeO[sub.2] –GO composites. The OER activity and stability were measured using cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The CeO[sub.2] –GO-3 electrocatalyst has a smaller Tafel slope (176 mV·dec[sup.−1] ) and lower overpotential (240 mV) than the other electrocatalysts. In addition, it exhibited high cyclic stability for up to 10 h. Therefore, the inexpensive CeO[sub.2] –GO-3 electrocatalyst is a promising OER candidate.