Fabrication of Z-scheme heterojunctions of CDs@WO₃/g-C₃N₄ nanocomposite photocatalyst with enhanced visible-light photocatalytic degradation of malachite green

In this study, the performance of monoclinic WO₃/g-C₃N₄ nanoparticles, an efficient visible photocatalyst, was enhanced using loaded carbon quantum dots (CDs). Moreover, the structure, morphology, and photoelectric performance of ternary photocatalytic composite materials were characterized. The photocatalytic performance of ternary photocatalysts was evaluated using malachite green (MG) as the degradation target; a degradation rate of up to 96.3% was achieved after visible-light irradiation for 80 min. WO₃/g-C₃N₄ catalyst with 10%-loaded CDs exhibited the highest photocatalytic degradation rate, which was 23 and 30.44 times higher than that of pure WO₃ and g-C₃N₄, respectively. Active species capture experiments showed that h⁺ and ·O₂⁻ are key factors in the MG light degradation process. Furthermore, system characterizations were performed to explain the feasible photocatalytic mechanism for removing MG under visible light irradiation.