One-step synthesis of WO3 nanoparticles using Spondias mombin aqueous extract: effect of solution pH and calcination temperature.

Abstract

In the present work, one-step green synthesis of WO3based on the interaction of ammonium paratungstate andSpondias mombin leavesextract is reported. Different concentrations of iodine and phosphorus in the range of(2%, 5% and 10%) were firstly incorporated into the prepared WO3nanoparticles to obtain Iodine doped andPhosphorus doped WO3nanoparticles respectively. Subsequently, iodine and phosphorus co-doped WO3na-nocomposites was prepared using a wet impregnation method followed by calcination at high temperature. Thenanomaterials were characterized by HRSEM, HRTEM, BET, UV–Visible, EDS, XRD and XPS. The photo-oxi-dation of dyeing wastewater by the synthesized WO3nanomaterials were tested and assessed using Total organiccarbon (TOC) and Chemical oxygen demand (COD) as indicator parameters. XRD and HRSEM analysis de-monstrated the formation of only monoclinic phase of WO3irrespective of the dopants. The UV–Visible diffusereflectance spectroscopy showed the band gap energy of 2.61 eV for undoped WO3and 2.02 eV for I-P co-dopedWO3nanocomposites. The surface area of I-P co-doped WO3(416.18 m2/g) was higher than the undoped WO3(352.49 m2/g). The XPS demonstrated interstitial and substitution of oxygen (O2−) vacancies in WO3by I−andP3+and formed I-P-WO(3-x). The I-P co-doped WO3exhibited higher catalytic activities (93.4% TOC, 95.1%COD) than the undoped (54.9% TOC, 79.2% COD) due to the synergistic effects between the two dopants. Theexperimental data better fitted to pseudo-second order than first order and pseudo-first order model. This studydemonstrated the enhanced photocatalytic performance of I-P co-doped WO3nanocomposites under sunlight.