0D/1D type II CdS/TiO2 nanocone arrays/Ti hybrids for visible-light-driven rapid photocatalytic degradation of tetracycline: An insight investigation of the interfacial electron transport mechanism

The photocatalytic applications of TiO2 was limited by its rapid photogenerated charge recombination and low responsiveness to visible light. To address these challenges, we introduced a novel low-dimensional heterojunction, CdS quantum dots/TiO2 nanocone arrays on Ti mesh substrate (referred to as CTNC), facilitating efficient separation of photogenerated carriers under visible light. Effective type II electron migration from TiO2 to CdS was established, enhancing charge separation, as confirmed by in situ irradiated Kelvin probe force microscopy (KPFM) and ultraviolet photoelectron spectroscopy (UPS). The comprehensive analysis of the photoelectric properties of conical TiO2 further confirmed the efficient separation of electron-hole pairs. Leveraging these advantages, the CTNC catalyst significantly degraded 83% of TC (20 mg/L) within 120 min (rate constant k = 0.029 min-1), outperforming CTNR (CdS quantum dots/TiO2 nanorod arrays on Ti substrate) by 2.6 times, and surpassing related low-dimension heterostructures of CdS/TiO2 in previously reported. Remarkably, CTNC exhibited exceptional TC degradation performance and stability on both fronts. The present study provides profound insights into enhancing the photocatalytic performance of TiO2 through morphology manipulation and the formation of heterojunctions responsive to visible light.