Engineering copper/cadmium doping of MoSe2 for efficient photocatalytic oxytetracycline removal

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The strategy of metal ion doping of MoSe2 effectively improves photocatalytic performance. Herein, we investigated the effect of MoSe2 doping and co-doping on the photocatalytic degradation of oxytetracycline (OTC) antibiotic in aqueous media. As-synthesized samples were characterized by powdered X-ray diffractometry, Raman spectroscopy, UV–vis absorption spectroscopy, photoluminescence spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Cu2+ doping does not significantly alter the MoSe2 band gap, but Cd2+ doping increases the MoSe2 band gap. Likewise, CuCd-MoSe2 exhibits an intermediate band gap. The photocatalytic activities were tested by degrading TC under incandescent light irradiation. The results show that Cu-MoSe2 performs the best with photocatalytic degradation of almost 97% of OTC in just 50 min, with the highest K app (0.059 min−1). Cu-MoSe2 exhibits the lowest anodic-cathodic peak-to-peak ratio (ΔEp) of all the as-synthesized samples, indicating a higher electron transfer. Moreover, the largest anodic current density given by Cu-MoSe2 reflects a more efficient electron transfer. In brief, the doping enhances photocatalytic performance compared to co-doping. This study highlights the critical importance of metal ion doping in semiconductors.