High photoactivity of ZrxOy-Bi2O2(CO3) composite materials prepared by one-step synthesis for efficient photodegradation of 4-chlorophenol in water

Abstract

The ZrBi composite materials were prepared in a single step by the chemical co-precipitation method. Bi2O2(CO3) joined ZrxOy modifying the mole percentage from 5 to 11 mol %. ZrBi composites dried at 80 °C were characterized by: XRD, FTIR, DRS, SEM, N2 adsorption, HR-TEM, PL, XPS and EDS-SEM. Later they were evaluated in the photodegradation of 4-Chlorophenol under UV irradiation. The degradation and mineralization percentages were determined after 150 min of reaction by UV–vis spectroscopy and Total Organic Carbon (TOC), respectively. The composite containing 9 mol % of Bi2O2(CO3) (ZrBi-9) with a specific volume of 0.03 m3/kg in solution with specific catalyst density of 1*10−3 kg/L, showed the highest photoactivity with 96 % photodegradation, a higher value compared to that obtained with the reference material TiO2-P25 (72 %). Finally, a possible reaction mechanism was proposed based on recent studies, which allow to follow the formation of active species OH, O2− and h+. The formation of OH radicals was measured by fluorescence spectroscopy while the inhibition of O2− radicals as well as the scavenge of h+ were determined by UV–vis spectroscopy. The results showed that ZrBi composite materials do not promote OH radical formation. The scavenge of h+ showed a total loss of photoactivity and the inhibition of O2− in the reaction medium results in a partial decrease of photoactivity. The formation of heterojunctions, the presence of localized states and oxygen vacancies in the synthesized materials promise an excellent alternative for the rapid photodegradation of 4-Chlorophenol under UV radiation.