Graphene-mediated Photocatalytic removal of Cephalothin by CaTa₂O₆

Graphene contributes greatly to the photocatalytic performance of semiconductors, but the role that graphene plays in these photocatalysts is not clear. Here, we report for the first time the combination of calcium tantalate (CaTa₂O₆) perovskite with reduced graphene oxide (rGO) as effective photocatalysts for environmental remediation. In the adsorption/degradation experiments with cephalothin as the target pollutant, we found that the CaTa₂O₆/rGO composites exhibited enhanced photocatalytic activity and adsorption performance with an optimum degradation rate of 80.91% compared to the pure phase CaTa₂O₆, which may be attributed to the synergistic effects of the enhanced adsorption of dye molecules on the surface of the rGO and the fact that the rGO as an electron acceptor promotes the separation of photogenerated carriers. In the degradation mechanism, we explored the degradation pathway of cephalothin and the role of active radicals in the catalytic system. Furthermore, the excellent stability and recyclability of the CaTa₂O₆/rGO photocatalysts were confirmed by five-cycle catalytic experiments, suggesting that these materials can be used as viable and stable photocatalysts for environmental remediation.