Abstract
Addressing the global water crisis requires advanced solutions for persistent pollutants like methylene blue (MB), where traditional TiO(2) photocatalysis is limited by wide bandgap and charge recombination. This study develops a nitrogen-doped carbon-modified TiO(2) (mNC-TiO(2)) photocatalyst to overcome these challenges, combining nitrogen doping (2.5%) with a conductive carbon matrix to enhance visible-light absorption, charge separation, and wastewater treatment efficacy. The material was synthesized via a microemulsion-liquid crystal template method, forming a mesoporous nanostructure (298 m(2) g(-1) surface area, 5.4 nm pores) with oxygen vacancies and reduced bandgap (2.85 eV). Characterization (XRD, XPS, FE-SEM, EDX, and HR-TEM) verified its optimized structure, while photocatalytic tests achieved 94.7% MB degradation under UV-3.1× more efficient than dark adsorption (30.1%). The reaction followed pseudo-first-order kinetics (k (1) = 4.8 × 10(-2) min(-1)), with ˙OH and ˙O(2) (-) as dominant oxidants. Remarkably, mNC-TiO(2) retained > 85% efficiency over five cycles due to its stable mesostructure and HNO(3)-regenerable sites. The carbon matrix served dual roles as electron acceptor and molecular adsorbent, synergizing with nitrogen-induced bandgap narrowing for sustained performance. These results demonstrate a rationally designed photocatalyst with practical potential for organic pollutant removal.