Exceptional visible-light-induced photocatalytic activity of attapulgite–BiOBr–TiO2 nanocomposites

A novel and efficient visible-light-responsive attapulgite composite photocatalyst was fabricated by introducing BiOBr–TiO2 hybrid oxides onto its surface using in-situ depositing technique (marked as ATT–BiOBr–TiO2). ATT–BiOBr–TiO2 nanocomposites with different molar ratios of r (r = nTi / (nTi + nBi) were studied in order to achieve the best photocatalyst. The obtained samples were characterized by XRD, TEM, SEM and BET measurements. It was shown that BiOBr–TiO2 nanocomposite particles with average size of 10 nm were introduced onto attapulgite fibersʹ surface without obvious aggregation. Compared with ATT, ATT–TiO2, ATT–BiOBr and BiOBr–TiO2, ATT–BiOBr–TiO2 exhibits exceptional visible-light photocatalytic activity in degradation of 20 mg·L− 1 methyl orange. The photodecomposition % of methyl orange increased along with the increasing content of TiO2 in the case of r ≤ 0.83 and decreased as r > 0.83. 96.80% of methyl orange was removed by using ATT–BiOBr–TiO2 (r = 0.83) within 120 min. Possible mechanism was put forward.