N-CQDs act as electronic warehouse in N-CQDs/CdS regulate adsorption energy to promote photocatalytic selective oxidation of aromatic alcohols

Lignin-derived red carbon dots sensitized TiO2 photocatalysts for tetracycline degradation

To extend the photo-response range and quantum efficiency of titanium dioxide (TiO2), it was sensitized with lignin-derived red-emitting carbon dots (RCDs). The RCDs consisted of a base lignin structure and many types of functional groups (e.g., CO, -NH2, -OSO3H, -NR2, and -OH). The optimal emission wavelength of the RCDs was 628 nm, with a fluorescence lifetime of 8.56 ns. The TiO2 photocatalyst particles were sensitized by RCDs, which narrowed the band gap of TiO2 and increased the efficiency of carrier photogeneration. The RCDs/TiO2 possessed a double band-gap structure with the band-gap energies of 1.60 and 3.13 eV. The photocurrent response of RCDs/TiO2 under simulated solar irradiation were 1.2 to 4.5 μA·cm-2. The sensitization of TiO2 by RCDs facilitated the photocatalytic degradation of tetracycline. Under simulated sunlight, the degradation of tetracycline by RCDs/TiO2 reached 95.0 % and the mineralization ratio was 57.5 % within 60 min.

Carbon-Based Nanomaterials for Catalytic Wastewater Treatment: A Review

Carbon-based nanomaterials (CBM) have shown great potential for various environmental applications because of their physical and chemical properties. The unique hybridization properties of CBMs allow for the tailored manipulation of their structures and morphologies. However, owing to poor solar light absorption, and the rapid recombination of photogenerated electron-hole pairs, pristine carbon materials typically have unsatisfactory photocatalytic performances and practical applications. The main challenge in this field is the design of economical, environmentally friendly, and effective photocatalysts. Combining carbonaceous materials with carbonaceous semiconductors of different structures results in unique properties in carbon-based catalysts, which offers a promising approach to achieving efficient application. Here, we review the contribution of CBMs with different dimensions, to the catalytic removal of organic pollutants from wastewater by catalyzing the Fenton reaction and photocatalytic processes. This review, therefore, aims to provide an appropriate direction for empowering improvements in ongoing research work, which will boost future applications and contribute to overcoming the existing limitations in this field.

Recent Progress on Carbon Quantum Dots Based Photocatalysis

As a novel carbon allotrope, carbon quantum dots (CQDs) have been investigated in various fields, including photocatalysis, bioimaging, optoelectronics, energy and photovoltaic devices, biosensing, and drug delivery owing to their unique optical and electronic properties. In particular, CQDs' excellent sunlight harvesting ability, tunable photoluminescence (PL), up-conversion photoluminescence (UCPL), and efficient photo-excited electron transfer have enabled their applications in photocatalysis. This work focuses on the recent progress on CQDs-related materials' synthesis, properties, and applications in photocatalysis.