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To completely utilize the high redox ability of photo-induced charge carriers. Here, a Z-scheme photocatalyst of TiO2 QDs/Bi12TiO20 (TBT) composites with TiO2 QDs fragment attached to the surface of Bi12TiO20 (BTO) was prepared and the photocatalytic activity was evaluated by degradation of gatifloxacin (GF). The optimal photocatalytic performance of TBT displayed 3 times higher than bare BTO. The improved photocatalytic performance was ascribed to the effective separation of the charge carriers between TiO2 QDs and BTO via the direct Z-scheme heterojunction. Such a strategy for the construction of Z-scheme TBT composites for removal of organic pollutants, proving new insights into design photocatalyst.

Herein, we report a novel ternary material comprised of Ag nanoparticles and carbon quantum dots (CDs), which are co-loaded using 2D Bi4Ti3O12 (BIT) sheets. In this system, Ag can be applied as excited electron-hole pairs in the Bi4Ti3O12 by transferring the plasmonic energy from the metal to the semiconductor. The surface plasmon resonance of Ag can promote the electron transfer properties of the CDs, thereby improving the separation efficiency of the electron-hole pairs. Meanwhile, the CDs can act as an electron buffer to decrease the recombination rate of the electron hole. Moreover, CDs are prepared using a biomaterial, which can provide a chemical group to enhance the electron transfer and connection. The synergistic effects of CDs, Ag, and BIT enable the design of a photocatalytic application with a remarkably improved efficiency and operational stability.

In this paper, a simple in-suit method was used to load CdSe quantum dots (QDs) onto HTC (abbreviated as Hydrothermal biochar, HTC) to form CdSe/HTC composites. Fourier transform infrared spectrometer and X-ray photoelectron spectroscopy were used to detect and analyze the surface valence and composition of CdSe/HTC composites. The photocatalytic degradation activity was judged by photodegrading tetracycline (TC). Compared with pure CdSe quantum dots, the best photocatalytic degradation efficiency of CdSe/HTC complex containing 15% HTC was 73%, which was attributed to the high carrier transport efficiency of HTC and the inhibition reorganization of photogenerated electron-hole pairs. More importantly, the hydrothermal biochar used in this paper was extracted from waste biomass and had the characteristics of economy, environmental protection and high utilization rate, and was in line with the basic viewpoint of sustainable use of resources.

In this work, a simple method to load of g-C3N4 quantum dots (CN QDs) onto Bi2Ti2O7 (BTO) microsphere with the amount of CN QDs (3, 7, 10 and 15%). The photocatalyst was used for the treatment of water pollutants under visible-light illumination, which proved that CNBTO composites showed improved photocatalytic activity matched up to pure BTO. Reformation of BTO with CN QDs enhanced the light assimilation capacity, and promoted the isolation of photo-induced electron-hole pairs. The trapping experiments and ESR were announced the holes (h+) and superoxide oxide (O2 −) played the key role, and the relative mechanism of the photocatalytic process was proposed. Meanwhile, the effects of CN QDs content, pH and initial pollutant concentration on the removal efficiency of ciprofloxacin (CIP) were studied. Results showed that the CN QDs loaded on BTO presented higher photocatalytic efficiency, and an optimum value for the dosage of photocatalytic in pH 8.0.