Pollution

Pollution

Facile Control of Anatase-Rutile Phase Ratio in TiO2 Nanoparticles for Highly Efficient Photocatalytic Degradation of Methylene Blue

Articles in Press

Document Type : Original Research Paper

Authors
Tran Quoc Tuan 1
Nguyen Xuan Quang 1
Tien Van Manh 2
Nguyen Van Toi 3
Nguyen Van Quang 4
Lu Thi Yen 1
Ong Van Hoang 1
1 Faculty of Applied Science, University of Transport Technology, Trieu Khuc, Thanh Liet, Hanoi 100000, Vietnam
2 Faculty of Information Technology, University of Transport Technology, 54 Trieu Khuc, Hanoi 100000, Vietnam
3 Vinh Phuc College of Engineering and Technology, Phu Tho, Vietnam
4 Hanoi Pedagogical University 2, Phu Tho, Vietnam
10.22059/poll.2026.414221.3330
Abstract
Spherical TiO₂ nanoparticles with tunable phase compositions were successfully synthesized via a one-step hydrothermal method by modulating HNO₃ dosage. The results reveal that acidity plays a decisive role in governing nucleation kinetics, particle size, and phase evolution from pure rutile to anatase–rutile mixed structures. XRD analysis confirms a transition from 100% rutile (1 mL HNO₃) to optimized mixed phases (62.8% anatase/37.2% rutile at 3 mL and 73.7% anatase/26.3% rutile at 5 mL). This structural evolution is accompanied by particle size refinement from 14.1 nm to 12 nm and enhanced surface hydroxylation. Optical studies show that the 3-HNO₃ sample exhibits the lowest photoluminescence intensity and a reduced bandgap (3.05 eV), indicating efficient charge separation. As a result, this sample delivers superior photocatalytic performance, achieving 99% Methylene Blue removal within 150 min under UV irradiation, with a high apparent rate constant of 0.028 min⁻¹. The enhanced activity is attributed to the synergistic effect of optimized anatase-rutile heterojunctions and nanoscale size control, which promote interfacial charge transfer and suppress electron-hole recombination. This work provides a simple yet effective strategy for phase engineering of TiO₂ toward high-performance photocatalytic applications.
Keywords
TiO2 nanoparticle
Phase control
Anatase-Rutile heterojunction
Photocatalysis
Methylene Blue
Pollution

Articles in Press, Accepted Manuscript
Available Online from 11 August 2026