Green Synthesis of Ce-MOF/Ag Composites with Improved Electrocatalytic Activity and Stability for Sustainable Water Splitting

Abstract This study was focused on preparing an MOF-based composite to enhance its efficiency in water splitting applications. The MOF framework was enhanced with additional active ingredients to boost its overall performance, stability, and catalytic activity. Developing such advanced composites is crucial for addressing the challenges of energy conversion and hydrogen generation via water splitting, which is considered a clean and sustainable route for future energy systems. A metal–organic framework (MOF) containing cerium and MOF-Ag composites have been synthesized using the green methodology. The generated materials were examined using several analytical methods, including contact angle, powder X-ray diffraction (PXRD), Brunauer-Emmett-Teller (BET), and scanning electron microscopy (SEM). The average particle size of the synthesized MOF-Ag composites ranges from 36.7 to 41.3 nm, which is confirmed by the SEM data in combination with the Gaussian mixture model. The BET and contact angle data confirm the mesoporous and hydrophilic characteristics of the MOF-Ag composites. The activity of the modified Ce-MOF and MOF-Ag composites electrode was utilized for water-splitting purposes. The current flowing through the electrodes lasts for five hours. The electrodes (MOF, MOF-Ag1, MOF-Ag2, and MOF-Ag3) attained the current density of 10 mA cm − 2 at overpotentials of ‒1.36, ‒1.08, ‒1.15, and ‒1.13 V (vs Ag/AgCl) for HER and at potentials of 2.1, 1.87, 1.92, and 1.98 V (vs. Ag/AgCl) for OER, respectively. Additionally, each of the changed surfaces (MOF, MOF-Ag1, MOF-Ag2, and MOF-Ag3) had its Tafel slopes calculated¸ yielding values of 150, 76, 86, and 91 mV dec − 1 for HER and 178, 90, 128, and 138 mV dec − 1 for OER.