MOF-derived FeCe@Carbon catalysts for the efficient tetracycline degradation by activated persulfate: Preparation and mechanistic study

Metal-organic frameworks (MOFs) derived materials are extensively utilized in wastewater treatment owing to their remarkable catalytic efficacy and durability. This study exploited iron-cerium-based bimetallic metal- -organic framework (FeCe-MOF) as a sacrificial template, which was subsequently calcined at 700 degrees C to produce an iron-cerium-based bimetallic carbon nanospheres (FeCe@C). The FeCe@C has active sites of bimetallic Fe and Ce derivatives, demonstrating exceptional activation efficiency for persulfate, resulting in approximately 98.2 % elimination of tetracycline hydrochloride (TCH) within 120 min. This removal rate markedly exceeds that of the individual iron-based carbon nanospheres (Fe@C) (53.6 %) and cerium-based carbon nanospheres (Ce@C) (78.3 %). Characterization results, including X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR), demonstrate that the Fe and Ce composite induces coordination unsaturation at the metal centers, leading to the formation of oxygen vacancies and an increase in active reaction sites. Additionally, radical quenching, EPR and electrochemical experiments demonstrate that radical (center dot OH, O2 center dot- and SO4 center dot-) and non- radical routes (O2 center dot-, 1O2 and electron transfer) synergistically catalyze the degradation of TCH. The observed increase in catalytic activity can be primarily ascribed to the synergistic interactions among multivalent metal ions and the rapid regeneration of metals in lower oxidation states. A potential degradation process for