Synthesis of V-modified TiO2 nanorod-aggregates by a facile microwave-assisted hydrothermal process and photocatalytic degradation towards PCP-Na under solar light

Abstract

Herein, novel V-modified titania nanorod-aggregates (VTNA), consisting of fine individual nanorods in radial direction, were fabricated via an efficient microwave-assisted hydrothermal (MWH) route. VTNA with high crystallinity and homogeneous mesopores were obtained by 30 min MWH processing at 190 °C; moreover, a mixed rutile–anatase phase appeared after vanadium doping. XPS analysis revealed that vanadium existed in the forms of V⁴⁺ and V⁵⁺ on the surface of MWV05 with V⁵⁺ being the dominant component, the content of which was approximately 3.5 times that of V⁴⁺. Vanadium implanting was achieved efficiently by doping 0.5 and 1 at% V using a rapid MWH process and contributed towards the dramatic improvement of the visible-light response, with E_g decreasing from 2.91 to 2.71 and 2.57 eV with the increasing V doping content. MWV05 exhibited optimal photocatalytic degradation activity of water-soluble PCP-Na under solar light irradiation. The enhanced photodecomposition was attributed to the red-shift in the TiO₂ band-gap caused by vanadium impregnation, efficient charge separation due to the V⁴⁺/V⁵⁺ synergistic effects and the free migration of charge carriers along the radial direction of the nanorods arranged in a self-assembled VTNA microstructure.