Facile surface modification of immobilized rutile nanoparticles by non-thermal glow discharge plasma: Effect of treatment gases on photocatalytic process

The aim of this study was to enhance the photocatalytic performance of commercial rutile TiO₂ nanoparticles using non-thermal glow discharge plasma methodology. Due to the lower photocatalytic performance compared to the anatase phase, the rutile phase has seldom been explored by researchers, despite its significant advantages. Nanoparticles of rutile TiO₂ were immobilized on glass plates using heat attachment method whose surface properties were modified by non-thermal glow discharge plasma using different gases. XRD, FE-SEM, UV-DRS, XPS, PL, and BET analyses were performed for physiochemical characterization of rutile nanoparticles. While the stable rutile crystalline phase remained intact, a variety of physiochemical modifications were observed. XPS analysis revealed diminished titanium to lattice oxygen ratio, suggesting the formation of surface oxygen vacancies. Pseudo-first-order reaction rate for photocatalytic degradation of malachite green was improved by 3.31, 2.22, and 1.83 times over unmodified photocatalysts using argon, oxygen, and nitrogen gases, respectively. The proposed surface modification method remarkably improved the photocatalytic performance of immobilized rutile nanoparticles without adding any impurities to its structure. Further, the reusability of plasma-treated photocatalysts was satisfying, where the relative decolorization efficiency dropped by 4.4% after four consecutive 60-minute cycles, suggesting a good potential for operation in wastewater treatment reactors.