Degradation of PCP-Na with La–B co-doped TiO 2 series synthesized by the sol–gel hydrothermal method under visible and solar light irradiation

Abstract

A series of photocatalysts was synthesized by doping TiO 2 with La and B via the sol–gel hydrothermal route. The photocatalytic capability of the catalysts under visible and solar light was evaluated in terms of sodium pentachlorophenate (PCP-Na) decomposition and dechlorination. The structural and physicochemical properties of these nanocatalysts were characterized by XRD, DRS, ICP-OES, TEM, XPS, and N 2 adsorption–desorption techniques. B doping enlarged the anatase framework, and La doping hindered the crystallization and growth of the mesoporous structure in both singly La-doped and La–B co-doped catalysts. B implantation mainly resulted in visible-light response, whereas overload La 2O 3 coating worsened visible light absorption, as confirmed by DRS and XPS. XPS and ICP-OES analyses revealed that the B and La content increased approximately by 1.6 and 4.8 times from the interior to the surface of modified TiO 2, which dominantly existed in the form of La 2O 3 and interstitial B structure. The co-doped sample with 1% La and 5% B doping (LA10B50) exhibited maximum photocatalytic activity under visible and solar light compared with the mono-doped samples, which was attributed to synergetic effects, namely, efficient separation of photo-generated carriers by La and response to the extended visible region due to B. An increase in hydroxyl groups and the photosensitivity of carbon on the surface also contributed to the improvement of photoactivity.