Work

One-step fabrication of C-modified TiO2 composite photocatalysts for enhanced visible light photocatalytic performance

Year: 2025

Type: article

Abstract: • C-modified TiO₂ (Cs-Ti) made via one-step sol-gel plus hydrothermal method. • Cs-Ti shows higher MB degradation under visible light than TiO₂ or P25. • 98.99 % MB removal achieved via response-surface optimized conditions. • ESR and photoelectrochemical tests confirm •O₂⁻/•OH and suppressed recombination. In this research, a carbon-modified TiO 2 photocatalyst (Cs-Ti) was synthesized via a novel one-pot sol-gel co-condensation process coupled with low-temperature hydrothermal treatment, using chitosan as a sustainable carbon source. This integrated approach enables simultaneous in situ carbon doping and TiO 2 crystallization in a single reaction sequence, eliminating the need for post-synthesis calcination or secondary carbon coating steps typically required in conventional methods. The optimized Cs-Ti-7.4 exhibited a specific surface area of 245 m 2 g −1 , which is nearly 1.2 times that of pure TiO 2 . Additionally, compared to pure TiO 2 , the band gap energy of Cs-Ti has also decreased, enabling strong visible light absorption. Characterization via XRD, Raman spectroscopy, XPS, and UV–Vis confirmed successful substitutional carbon doping and formation of anatase-phase nanoparticles. Photocatalytic degradation of methylene blue (MB) under visible light was systematically optimized using response surface methodology. At the optimal conditions—initial MB concentration of 10.04 mg L −1 , catalyst dosage of 54.86 mg L −1 , pH 7.99, and 90 min irradiation—the Cs-Ti-7.4 achieved a 98.99 % removal rate. The influence of hierarchy on degradation efficiency was determined to be: MB concentration > doping ratio > pH. Cs-Ti-7.4 exhibited remarkably high visible-light photocatalytic activity in the degradation of MB, and the apparent rate constant of Cs-Ti-7.4 for MB removal was 3.1 times higher than that of pure TiO 2 . Radical scavenging experiments identified holes, superoxide radicals (•O₂⁻), and hydroxyl radicals (•OH) as the primary reactive species. The Cs-Ti catalyst maintained >95 % activity after five consecutive cycles, demonstrating excellent stability. This one-pot synthesis reduces processing time compared to traditional multi-step methods, while delivering superior visible-light photocatalytic performance, making it highly promising for scalable wastewater treatment applications.

Source: Results in Engineering

DOI: 10.1016/j.rineng.2025.108566

Authors: Ruixue Fan, Funing Zhang, Luqi Wang, Yunqing Liu, Jinghua Liu

Institutions: Yili Normal University, Dalian University of Technology

Language: English

Topic: TiO2 Photocatalysis and Solar Cells

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

SDGs: Responsible consumption and production, Affordable and clean energy

Open Access status: gold

Estimated APC paid: $1,940