Enhanced photocatalytic performance of a rGO-Ca₂Fe₂O₅ nanocomposite for photodegradation of emergent pollutants

In this study, a simple thermal reduction process is used to synthesize a rGO-Ca2Fe2O5 (rGO-CFO) nanocomposite, with the morphological and optical characteristics of the CFO nanomaterial being modified by the rGO incorporation. The interface between rGO nanosheets and CFO nanoparticles facilitates efficient charge separation and resulting transfer of photogenerated charge carriers across the rGO nanosheets, demonstrated from photoluminescence and Mott-Schottky tests. Compared to CFO (2.1 eV), rGO-CFO has a reduced band gap energy of 1.9 eV. As synthesized nanocomposites were initially optimized and utilized for photodegradation of organic effluent Methylene blue (MB). An addition of 5 wt% rGO to the CFO demonstrated an improved photodegradation efficiency (97%) compared to bare CFO (72%). An active species trapping experiment was used to assess the MB photodegradation mechanism. The results demonstrate that hydroxyl radicals and holes are the major active species involved in photodegradation. The optimized composition (5rGO-CFO) was further tested for degradation of Bisphenol-A and Tetracycline (antibiotic). Altogether, these investigations show that the rGO-CFO is a highly efficient photocatalyst that can be used to remediate emerging contaminants in sunlight.