Abstract: The photoabsorption capacity, the number of active sites, and the efficiency of carrier separation of photocatalysts are the main factors that restrict photocatalytic activity. Accordingly, a series of novel CdO-based S-scheme photocatalysts are prepared by a facile one-step precipitation-calcination method for the first time. Although CdO with a narrow band gap has no photocatalytic hydrogen evolution performance, the CdMoO₄/CdO composite exhibits excellent photocatalytic activity. The photocatalytic hydrogen evolution (PHE) performance of the optimal ratio (3:4) is up to 7029 µmol g^-1 h^-1 under visible light irradiation. At the same time, the CdMoO₄/CdO composite also shows excellent degradation activity of water pollutants, and the degradation efficiency for Tetracycline hydrochloride, Oxytetracycline, Norfloxacin, Reactive red 2, and Levofloxacin is 96.33%, 95.38%, 88.48%, 95.93%, and 77.30% under visible light irradiation for 90min, respectively. According to the experimental characterization and theoretical calculation analysis, the introduction of CdMoO₄ can be used to construct S-scheme heterojunction with CdO, improving the efficiency of charge separation as well as taking full advantage of redox ability, and hence improving superior photocatalysts performance. This work affords new insights into efficient PHE and antibiotic/dye degradation of CdO-based S-scheme photocatalysts.

Key words: CdMoO₄, CdO, S-scheme heterojunction, Hydrogen evolution, Antibiotics degradation